SecondaryCode 5129
Combined Science
78 topics and 327 objectives, each one something you should be able to do.
Written by Kindred in its own plain words. Your syllabus is still the official list, so check it for anything exact.
What this subject asks you to be able to do
1.1Cell structure and function4 objectives
- Identify the mitochondria, nucleus, cytoplasm and cell membrane found in an animal cell, from diagrams, photomicrographs or electron micrographs.
- Identify the mitochondria, chloroplasts, nucleus, sap vacuole, cytoplasm, cell membrane and cellulose cell wall found in a plant cell, from diagrams, photomicrographs or electron micrographs.
- Describe the functions carried out by the structures mentioned above, in both animal and plant cells.
- Understand that cells may become specialised, with the structures of each one matched to the particular function it carries out, as seen in the examples studied across this subject
1.2Movement into and out of cells6 objectives
- Outline what water does as a solvent within living things, relating this to digestion, excretion and transport
- Understand diffusion as molecules or ions spreading out through their random movement, so that there is a net movement from where their concentration is higher to where it is lower (i.e. down a concentration gradient)
- Outline how surface area, temperature, concentration gradients and distance each influence how quickly diffusion occurs
- Understand osmosis as water molecules making a net movement across a partially permeable membrane, from where the water potential is higher to where it is lower (working out water potential values is not required)
- Describe how osmosis affects plant and animal tissues, and explain why the water potential gradient and osmosis matter when water is taken up and lost
- Investigate and account for how plant tissues are affected when placed in solutions of differing concentrations, using the terms turgid, turgor pressure, plasmolysis and flaccid
2.1Enzyme action6 objectives
- Describe a catalyst as a substance which speeds up a chemical reaction while not itself being changed by it
- Describe enzymes as a kind of protein that acts as a biological catalyst
- Understand that most enzymes work inside the cell where they are made, which is how a cell keeps control of its metabolic activities
- account for how an enzyme works, referring to the substrate, active site, enzyme-substrate complex and product
- account for enzyme specificity in terms of the active site's complementary shape and how well it fits the substrate
- Investigate and explain how changing temperature and pH alters enzyme activity, using the ideas of denaturation, kinetic energy, shape and fit, and the frequency of effective collisions
3.1Photosynthesis6 objectives
- Understand that photosynthesis is the process through which plants manufacture carbohydrates out of raw materials, powered by light energy
- Give the word equation for photosynthesis, along with its balanced chemical equation
- State that chlorophyll, a green pigment, is located inside chloroplasts
- State that chlorophyll turns light energy into chemical energy, this energy then being used to form glucose and other carbohydrates
- Outline how the carbohydrates made in photosynthesis are then used and stored, limited to: (a) starch, kept as an energy store (b) cellulose, for building cell walls (c) glucose, broken down in respiration to release energy (d) sucrose, the form carried through the plant (e) glucose combined with mineral ions to make other biological molecules, e.g. proteins
- Investigate and account for how changing light intensity affects the rate of photosynthesis, making use of submerged aquatic plants
3.2Leaf structure2 objectives
- State that most leaves are thin with a large surface area, and explain in what way each of these features is an adaptation for photosynthesis
- Identify and label, on diagrams or photomicrographs of a dicotyledonous leaf, its cuticle and its cell and tissue structures, and explain how each structure is adapted for photosynthesis and gas exchange, limited to: (a) guard cells and stomata (b) palisade and spongy mesophyll cells (c) vascular bundles (xylem and phloem) (d) air spaces (e) how the chloroplasts are distributed
3.3Transport in flowering plants5 objectives
- Relate the way root hair cells are structured to their function in taking up water and mineral ions
- Explain why these matter: (a) nitrate ions, used to make amino acids, which are needed to produce proteins (b) magnesium ions, used to make chlorophyll
- Outline the route water follows on its way through the root, stem and leaf, limited to: root hair cells, then cells of the root cortex, then the xylem, and finally mesophyll cells
- Describe transpiration as water evaporating from mesophyll cell surfaces into the air spaces, followed by water vapour diffusing out of the leaves via the stomata
- Describe translocation as the transport of sucrose and amino acids through the phloem from the sites that make them (sources) to the sites that use or store them (sinks)
4.1Diet6 objectives
- Name the elements from which (a) carbohydrates, (b) lipids (fats and oils) and (c) proteins are composed.
- State that glucose is the building block of starch, cellulose and glycogen, amino acids build proteins, and lipids are formed from glycerol combined with fatty acids
- Describe the chemical tests for the following, and be able to carry them out: (a) starch, using iodine solution (b) glucose and maltose, using Benedict’s solution (c) protein, using the biuret test (d) lipids, using the ethanol emulsion test
- Name the main food sources of carbohydrates, lipids, proteins, vitamins (C and D only), mineral ions (calcium and iron only), fibre (roughage) and water, and outline why each one matters in the diet
- Understand what is meant by a balanced diet
- Describe the signs of Type 2 diabetes, limited to a raised glucose concentration in the blood and glucose in the urine, and how it is treated through diet, exercise and/or giving insulin
4.2Human digestive system9 objectives
- Identify these main regions of the digestive system: the mouth, oesophagus, stomach, small intestine (duodenum and ileum) and large intestine (colon, rectum and anus), as well as the salivary glands, pancreas and liver
- Explain why the majority of foods must be digested before absorption is possible
- Describe physical digestion: food is broken up into smaller pieces, without the molecules in it being changed chemically
- State that physical digestion gives food a larger surface area for enzymes to act on during chemical digestion
- Describe chemical digestion as the process in which large molecules are broken down to give small molecules
- Describe what each main region of the digestive system does, limited to: (a) mouth – ingestion, physical digestion, and amylase digesting starch chemically (b) salivary glands – producing saliva, which contains amylase (c) stomach – physical digestion, protease digesting protein chemically, and hydrochloric acid in the gastric secretions (d) small intestine (duodenum and ileum) – chemical digestion in which amylase acts on starch, maltase on maltose, protease on protein and lipase on lipids (e) liver – storing glycogen, and breaking down excess amino acids to form urea, which the kidneys excrete (f) pancreas – an alkaline secretion that contains amylase, protease and lipase (g) ileum and colon – where absorption takes place (h) rectum and anus – where egestion takes place
- Describe the function of each of the enzymes amylase, maltase, protease and lipase, naming the substrates and products, limited to: (a) starch is broken down to maltose by amylase (b) maltose is broken down to glucose by maltase (c) protein is broken down to amino acids by protease (d) lipids are broken down to fatty acids and glycerol by lipase
- Describe the function of the stomach's hydrochloric acid: it kills bacteria that have been ingested
- Understand that the stomach and the duodenum contain different proteases, and that each of them has a different pH at which it works best
4.3Absorption and assimilation6 objectives
- State that the site of nutrient absorption is the small intestine.
- Appreciate that absorption refers to nutrients moving out of the intestines and into the cells that line the digestive system, before entering the blood.
- Appreciate that assimilation refers to cells taking in nutrients from the blood and making use of them.
- Explain why the larger internal surface area that villi give the ileum is important
- Understand that water is absorbed out of the lumen of both the colon and the small intestine, but that the small intestine takes in most of it
- State the hepatic portal vein's function: it is how most nutrients absorbed in the ileum reach the liver
5.1Human gas exchange4 objectives
- state and account for the ways in which inspired air and expired air differ
- identify, using diagrams and pictures, the larynx, trachea, lungs, bronchi, bronchioles, alveoli and the capillaries linked to them
- state that oxygen moves into the blood, and carbon dioxide moves out of the blood, across the alveoli, and that both of these transfers happen by diffusion
- Investigate and explain how physical activity affects breathing, in both its rate and its depth
6.1Respiration1 objective
- Describe respiration as chemical reactions, happening in every living cell, by which energy is released from glucose
6.2Aerobic and anaerobic respiration7 objectives
- Describe aerobic respiration as the process that releases a comparatively large quantity of energy through the breakdown of glucose where oxygen is present
- Give the word equation and the balanced chemical equation that represent aerobic respiration
- State that respiration produces carbon dioxide as a waste product, and that humans excrete it through their lungs
- Describe anaerobic respiration as the process that releases a comparatively small quantity of energy when glucose is broken down without oxygen
- Give the word equation that represents anaerobic respiration within human bodies
- Account for why lactic acid accumulates in muscles and blood during intense exercise, producing an ‘oxygen debt’
- Outline how the oxygen debt is cleared once exercise has finished, limited to: (a) a heart that keeps beating quickly so that lactic acid in the blood travels from the muscles to the liver (b) breathing that stays deeper and faster to bring in the oxygen needed for breaking lactic acid down in the liver
7.1Circulatory system7 objectives
- Describe the circulatory system as a system of blood vessels, featuring a pump and valves that guarantee blood moves in just one direction.
- Identify the structures of a mammalian heart in diagrams and photographs, limited to: the septum, the muscular wall, the left and right atria and ventricles, the coronary arteries, and the semilunar and atrioventricular valves
- Account for how thick the muscle walls are: (a) in the left ventricle compared with the right ventricle (b) in the atria compared with the ventricles
- Describe how the heart works, with reference to the contraction of the atrial and ventricular muscles and the role of the valves during one heartbeat.
- Investigate and explain how physical activity affects heart rate
- Describe coronary heart disease in relation to blocked coronary arteries, and state what its possible risk factors are, including age, gender, genetic predisposition, diet, stress, smoking and a sedentary lifestyle
- Discuss how diet and exercise can help to lower the risk of coronary heart disease
7.2Blood vessels3 objectives
- Name the main blood vessels by which blood enters and leaves the heart, lungs and liver, limited to: vena cava and aorta; pulmonary vein and pulmonary artery; hepatic artery, hepatic portal vein and hepatic vein
- Describe the structure of arteries, veins and capillaries, and identify it on diagrams and photomicrographs, limited to: (a) the wall's relative thickness (b) the wall's composition (muscle and elastic tissue) (c) the lumen's diameter (d) whether valves are present
- Explain the link between the structure of arteries, veins and capillaries and the pressure of the blood each one carries
7.3Blood2 objectives
- Identify, from diagrams and photomicrographs, the red and white blood cells (lymphocytes and phagocytes)
- State the function of each component of blood: (a) red blood cells – carry oxygen (b) white blood cells – lymphocytes produce antibodies and phagocytes engulf pathogens (c) platelets – cause clotting, which stops blood being lost and pathogens getting in (the mechanism of clotting is not required) (d) plasma (mostly water) – transports substances, limited to: blood cells, ions, glucose, amino acids, hormones, carbon dioxide, urea, vitamins and antibodies
8.1Drugs and their effects5 objectives
- Describe a drug: any substance that, after entering the body, modifies or affects the chemical reactions going on inside it
- outline how antibiotics are employed to treat infections caused by bacteria
- State that, by using antibiotics only when it is essential, the development of bacteria that resist antibiotics can be kept to a minimum
- outline the consequences of drinking alcohol in large amounts: weaker self-control, acting as a depressant, impact on reaction times, injury to the liver and wider social effects
- Describe the effects that tobacco smoke and its main toxic components (nicotine, tar and carbon monoxide) have: it is strongly associated with bronchitis, emphysema, lung cancer and heart disease, and smoking while pregnant is associated with babies having a reduced birth weight
9.1Human nervous system and hormones6 objectives
- State that body functions are coordinated and regulated by the nervous system, made up of the brain, spinal cord and nerves
- Describe the human nervous system by dividing it into: the central nervous system (CNS), made up of the brain and spinal cord, and the peripheral nervous system (PNS), made up of the nerves that lie beyond the brain and spinal cord
- State that changes in the environment are detected by sensory receptors, and that the body can then respond to them through the nervous system
- Describe a simple reflex arc as a pathway through a receptor, a sensory neurone, a relay neurone, a motor neurone and an effector (muscles and glands)
- Describe a reflex action as an automatic and fast response that a stimulus triggers
- Describe a hormone, e.g. insulin, as a chemical substance that a gland produces and the blood carries, and which changes how one or more of its specific target organs work
10.1Nuclear division7 objectives
- Understand that DNA (deoxyribonucleic acid) is found within chromosomes, and that this molecule carries genetic information, taking the form of genes
- State that a gene is a particular stretch of DNA holding the code required to produce a given protein, typically an enzyme
- State that in most cells the nucleus is diploid, holding two sets of chromosomes, while human cells have 23 pairs of chromosomes
- Describe mitosis as nuclear division that yields genetically identical cells while the chromosome number stays constant (stage-by-stage detail is not needed).
- Outline what part mitosis plays in growth, in mending damaged tissue and in replacing cells that die
- State that meiosis takes part in making gametes, and that in humans it happens only in the testes and ovaries.
- Describe meiosis as a reduction division that cuts the chromosome number in half, from diploid to haploid, producing cells that differ genetically (stage details are not required).
10.2Sexual reproduction in humans8 objectives
- Identify the testes, scrotum, sperm ducts, prostate gland, urethra and penis on a diagram showing the male reproductive system, and describe the function of each
- Identify the ovaries, oviducts, uterus, cervix and vagina on a diagram showing the female reproductive system, and describe the function of each
- Compare the gametes of males and females with regard to size, structure, numbers and motility.
- Describe fertilisation as the nucleus of a male gamete (sperm) fusing with the nucleus of a female gamete (egg cell), forming a zygote that then develops into an embryo
- Describe the menstrual cycle, covering how an egg develops and is released and how the lining of the uterus changes (knowing about the hormones involved is not required)
- Describe the routes of transmission of HIV (human immunodeficiency virus)
- Understand that an HIV infection could bring about Acquired Immune Deficiency Syndrome (AIDS).
- Describe the ways HIV can be kept in check.
11.1Biotechnology and genetic modification4 objectives
- Describe genetic modification as altering an organism's genetic material by taking out, putting in or modifying single genes
- Understand the reasons bacteria are useful for biotechnology and genetic modification: they reproduce at a rapid rate, they are able to make complex molecules, and there are no ethical concerns about manipulating and growing them
- Appreciate that the gene governing human insulin synthesis is placed into bacterial DNA to allow insulin to be produced commercially.
- State that crop plants may undergo genetic modification so they: resist herbicides, resist insect pests, can produce extra vitamins.
12.1Nutrient cycles and energy flow6 objectives
- Understand that most biological systems get their energy input mainly from the Sun
- account for why the majority of living things rely wholly on photosynthesis
- Describe the way energy flows along food chains, including the energy that comes from light, the energy in living organisms, and how it is eventually transferred to the environment
- account for why eating crop plants directly is the more efficient use of energy for people, compared with eating livestock reared on those same crops
- Understand that, as the human population grows, demand for resources across the world is rising
- Describe the carbon cycle, limited to: feeding, respiration, photosynthesis, combustion, the formation of fossil fuels, and decomposition together with the role of decomposers
12.2Effects of humans on ecosystems2 objectives
- Outline what drives deforestation, and describe what it leads to, limited to its influence on biodiversity, extinction, loss of soil, flooding and the concentration of carbon dioxide in the atmosphere
- Describe how people affect ecosystems by excessively harvesting plant and animal species, bringing a species that is not native into an ecosystem, polluting water with untreated sewage and fertilisers containing nitrogen, limited to the drop in dissolved oxygen and the deaths of organisms it causes, plastics that cannot biodegrade in the environment, in both aquatic and terrestrial ecosystems
13.1Solids, liquids and gases4 objectives
- State the properties which tell solids, liquids and gases apart
- Outline how solids, liquids and gases are built, covering how far apart their particles sit, how those particles are laid out, and how they move
- Describe and account for the way substances change state (melting, boiling, evaporation, freezing and condensing), using kinetic particle theory
- Describe and account for how temperature and pressure act on a gas's volume, drawing on kinetic particle theory
14.1Elements, compounds and mixtures4 objectives
- Outline how elements, molecules, compounds and mixtures differ from one another
- Describe what is meant by each of these: a solvent, which is a substance able to dissolve a solute; a solute, which is a substance that has been dissolved in a solvent; a solution, meaning a mixture in which one or more solutes have been dissolved into a solvent
- Outline the procedure for separating soluble substances in a mixture by paper chromatography, selecting an appropriate solvent to use
- Interpret simple chromatograms in order to identify unknown substances, by comparing them with known ones, and to tell whether substances are pure or impure
14.2Atomic structure and the Periodic Table6 objectives
- Describe how an atom is built, with a central nucleus made up of neutrons and protons and electrons arranged in shells around it
- Give the relative charge and relative mass of each particle: the proton, the neutron and the electron
- Define proton number/atomic number as the count of protons held in an atom's nucleus
- Define mass number/nucleon number as how many protons and neutrons there are altogether in an atom's nucleus
- Work out the electronic configuration of elements having proton numbers from 1 to 20, e.g. 2,8,3
- State that: (a) the noble gases, which make up Group VIII, are monatomic gases that do not react and have a full outer shell, e.g. 2,8 (b) in Groups I to VII, the group number tells you how many electrons are in the outer shell (c) the period number tells you how many shells contain electrons
14.3Ions and ionic bonds6 objectives
- Outline how positive ions (cations) and negative ions (anions) arise, with each ion ending up with a noble gas electronic configuration
- Describe ionic compounds as having a giant lattice structure, in which positive and negative ions alternate in a regular arrangement
- State that an ionic bond is the strong electrostatic attraction that acts between ions of opposite charge
- Outline how ionic bonds come about between ions from metallic and non-metallic elements, including sodium and chlorine forming NaCl and magnesium and chlorine forming MgCl2
- Apply dot-and-cross diagrams to demonstrate how ionic bonds are formed
- Describe the properties of ionic compounds and explain them using ideas about structure and bonding: (a) high melting and boiling points (b) electrical conductivity that is good when the compound is molten or aqueous, and poor when it is solid
14.4Simple molecules and covalent bonds3 objectives
- State that a covalent bond forms when two atoms share a pair of electrons, so that each reaches a noble gas electronic configuration
- Describe how covalent bonds are produced within simple molecules, including H2, Cl2, H2O, CH4, NH3, HCl, O2 and CO2. Use dot-and-cross diagrams to display the electron arrangements in these and similar molecules.
- Describe the following properties of simple molecular compounds, and explain them using structure and bonding: (a) low melting and boiling points, caused by weak intermolecular forces (the particular kinds of intermolecular forces are not required) (b) poor electrical conductivity
15.1Formulae5 objectives
- State the formula of every element and compound named in this subject's content
- Define a compound's molecular formula as the count and kinds of distinct atoms within a single molecule
- Deduce what formula a simple compound has, based on the ratio of atoms or ions drawn in a model or diagram
- Construct word and symbol equations that show the way reactants give rise to products, including state symbols
- Deduce a chemical reaction's symbol equation from the relevant information given
15.2Relative masses of atoms and molecules5 objectives
- Define relative molecular mass, Mr, as the total of the relative atomic masses; with ionic compounds, the quantity used is relative formula mass, Mr.
- Find the value of relative molecular mass together with relative formula mass.
- Calculate stoichiometric reacting masses
- Work out concentration, taken as the mass of solute that is dissolved within a particular volume of solution and measured in g/dm3
- Use balances, volumetric flasks and volumetric pipettes to make up a solution whose concentration is known
16.1Exothermic and endothermic reactions5 objectives
- state that an exothermic reaction gives off thermal energy to its surroundings, so the surroundings become warmer
- State that neutralisation and combustion both fall into the exothermic category.
- state that an endothermic reaction takes in thermal energy from its surroundings, so the surroundings become cooler
- state that the dissolving of ammonium nitrate and cracking both count as endothermic reactions
- Interpret data, including graphs, that record how temperatures shift during endothermic and exothermic reactions.
17.1Physical and chemical changes1 objective
- Identify changes as physical or chemical, and describe how the two kinds differ
17.2Rate of reaction4 objectives
- Describe the effect each of these has on the rate of a reaction: (a) a change in the concentration of a solution (b) a change in the surface area of a solid (c) a change in temperature (d) adding or removing a catalyst
- Explain that once a reaction is over, a catalyst is left unchanged
- Describe practical ways to find the rate of a reaction, including those that follow a gas being formed, and use and evaluate these methods
- Interpret the data from experiments on rate of reaction, including any graphs
17.3Redox5 objectives
- define redox reactions as those in which reduction and oxidation take place at the same time
- define oxidation as the gain of oxygen by a substance
- define reduction as the loss of oxygen by a substance
- Identify redox reactions as those in which oxygen is gained and lost
- Describe the glowing splint test for oxygen gas, O2, and use it to identify the gas
18.1The characteristic properties of acids and bases11 objectives
- State that acids in aqueous solution hold H+ ions, and alkalis in aqueous solution hold OH– ions
- State that a base is a metal oxide or metal hydroxide, and that an alkali is a base that is soluble
- Describe the properties that are characteristic of acids, as seen when they react with: (a) some metals (b) bases (c) carbonates
- Outline and apply tests that recognise these gases: (a) carbon dioxide, CO2, with limewater (b) hydrogen, H2, with a lit splint
- Describe the properties that are characteristic of bases, as seen when they react with: (a) acids (b) ammonium salts
- Outline and apply damp red litmus paper as a way of recognising ammonia gas, NH3
- State that acids and bases undergo a neutralisation reaction with each other
- Outline how an acid reacting with an alkali to form water is classed as a neutralisation reaction
- Outline how acids and alkalis affect: (a) universal indicator (b) litmus
- Describe how to use universal indicator to compare relative acidity, relative alkalinity and neutrality by colour and pH, and be able to do this
- State that an acid or an alkali can be corrosive
18.2Preparation of salts4 objectives
- Describe how soluble salts are made by letting an acid react with: (a) an excess of metal (b) an excess of insoluble base (c) an excess of insoluble carbonate
- Describe making an insoluble salt by precipitation (knowing which compounds dissolve is not required)
- Outline and account for the ways of separating and purifying substances by applying: (a) an appropriate solvent (b) filtration (c) crystallisation
- Outline the meaning of: (a) residue, a substance left over after evaporation, filtration or any comparable process (b) filtrate, a liquid or solution which has been passed through a filter
19.1Arrangement of elements5 objectives
- outline the layout of the Periodic Table, with elements placed in periods and groups and ordered by increasing proton number/atomic number
- outline the shift from metallic towards non-metallic character as one moves across a period
- outline how the group number of an element connects with the charge carried by the ions that element forms
- account for why elements within one group of the Periodic Table resemble each other chemically, by reference to their electronic configuration
- explain how knowing where an element sits in the Periodic Table lets us forecast its properties
19.2Group I properties4 objectives
- Describe lithium, sodium and potassium, the alkali metals of Group I, as metals that are relatively soft and that show general trends going down the group, limited to: (a) a decrease in melting point (b) an increase in reactivity with water
- Describe the Group I metals as flammable: they catch fire easily
- Describe and apply flame tests as a means of recognising Group I cations, limited to: (a) lithium, Li+, red (b) sodium, Na+, yellow (c) potassium, K+, lilac
- Predict the properties of other elements found in Group I, from the information given about those elements
19.3Group VII properties8 objectives
- Describe chlorine, bromine and iodine, the halogens of Group VII, as diatomic non-metals that show general trends going down the group, limited to: (a) an increase in density (b) a decrease in reactivity
- State how the halogens look at r.t.p.: (a) chlorine – a gas that is pale yellow-green (b) bromine – a liquid that is red-brown (c) iodine – a solid that is grey-black
- Describe the toxic nature of chlorine, Cl2, and of bromine, Br2
- Describe the way chlorine gas, Cl2, can be identified with damp litmus paper
- Outline and account for the reactions in which a halogen displaces other halide ions, and apply these reactions to rank the halogens by reactivity
- State how each halogen looks in aqueous solution: (a) chlorine is colourless (b) bromine is orange (c) iodine is brown
- Describe how halide ions react with acidified aqueous silver nitrate, giving insoluble silver halides, limited to: (a) AgCl, which is white (b) AgBr, which is cream (c) AgI, which is pale yellow
- Predict the properties of the remaining Group VII elements, using information supplied about them
19.4Identification of ions2 objectives
- Do tests, and use the information given about how aqueous anions react, to identify: (a) carbonate, CO32–, by adding dilute acid and checking whether carbon dioxide gas is given off (b) chloride, Cl–, bromide, Br–, and iodide, I–, by making the solution acidic with dilute nitric acid and then adding aqueous silver nitrate to it (c) sulfate, SO42–, by adding dilute nitric acid and aqueous barium nitrate
- Do tests and draw on supplied information about how aqueous cations respond to aqueous sodium hydroxide and aqueous ammonia, so that you can identify: (a) aluminium, Al3+ (b) ammonium, NH4+ (c) calcium, Ca2+ (d) chromium(III), Cr3+ (e) copper(II), Cu2+ (f) iron(II), Fe2+ (g) iron(III), Fe3+ (h) zinc, Zn2+
20.1Properties and uses of metals2 objectives
- Compare metals and non-metals in terms of their general physical properties, including: (a) thermal conductivity (b) electrical conductivity (c) ductility and malleability
- Describe how metals are used because of their physical properties, including: (a) aluminium is used to make aircraft since it has a low density (b) aluminium is used to make overhead electrical cables since it has a low density and good electrical conductivity (c) for food containers, aluminium is used since it resists corrosion (d) copper is used for electrical wiring since it has good electrical conductivity and is ductile
20.2Reactivity series4 objectives
- state that the reactivity series places metals in order, from the most reactive down to the least reactive
- describe how metals differ in reactivity, based on how readily they form positive ions and on any displacement reactions they undergo with aqueous magnesium, zinc, iron, hydrogen, copper and silver ions
- Deduce an order of reactivity for metals from experimental results you are given, based on: (a) metals reacting with cold water, steam and dilute hydrochloric acid so that hydrogen is displaced (b) metals in displacement reactions
- account for aluminium's apparent lack of reactivity by referring to its oxide layer
21.1Water5 objectives
- Describe distillation, which separates a liquid by means of evaporation followed by condensation
- Explain why, for practical work in chemistry, distilled water is preferred to tap water, since it has fewer chemical impurities
- State that water has to be treated before it is safe to drink
- Describe how the domestic water supply is treated, covering: (a) sedimentation and filtration, which remove insoluble solids (b) the use of carbon, which removes tastes and odours (c) chlorination, which kills microbes
- Describe desalination as a way of getting drinking water out of sea water
21.2Air quality and climate6 objectives
- Give the make-up of clean, dry air: about 78% nitrogen, N2, and 21% oxygen, O2, with the balance being noble gases plus carbon dioxide, CO2
- State where each of these air pollutants comes from: (a) carbon dioxide – complete combustion of fuels that contain carbon (b) carbon monoxide and particulates – incomplete combustion of fuels that contain carbon (c) methane – decomposition of vegetation, and the waste gases animals produce during digestion (d) gases – given off when plastics are burned
- State the harmful effect of each of these air pollutants: (a) carbon dioxide – more of it in the air increases global warming, and this causes climate change (b) carbon monoxide – a toxic gas (c) particulates – a greater risk of cancer and respiratory problems (d) methane – more of it in the air increases global warming, and this causes climate change (e) gases from burning plastics – toxic
- State and explain ways of reducing global warming, limited to: using more renewable energy, using fewer fossil fuels, limiting deforestation and reducing livestock farming
- State that a hydrogen–oxygen fuel cell generates electricity from hydrogen and oxygen; water is the only chemical product it yields
- Describe how hydrogen–oxygen fuel cells compare with gasoline/petrol engines as a way to power vehicles, giving their advantages and disadvantages
22.1Names and formulae of organic compounds4 objectives
- State that a structural formula shows, with no ambiguity, the arrangement of the atoms in a molecule
- Draw and make sense of the displayed formula of a molecule, showing every atom and every bond
- Name unbranched (a) alkanes and (b) alkenes having at most three carbon atoms in a molecule, and draw and interpret their structural and displayed formulae
- State which type of compound is present, from its chemical name if this ends in –ane or -ene, or else from its molecular, structural or displayed formula
22.2Fuels7 objectives
- Name coal, natural gas and petroleum as the fossil fuels
- Name methane as what natural gas is mainly made of
- State that compounds called hydrocarbons consist of hydrogen and carbon only
- State that petroleum consists of different hydrocarbons mixed together
- Describe how fractional distillation separates petroleum into useful fractions
- Describe how the properties of the fractions from petroleum change from the bottom of a fractionating column to the top, as they are collected, limited to: decreasing chain length, higher volatility, higher flammability, lower boiling points, lower viscosity
- Give the applications of each fraction: the refinery gas fraction, used to heat homes and cook; the gasoline/petrol fraction, which powers cars; the naphtha fraction, employed as a feedstock for chemicals; the kerosene/paraffin fraction, serving as jet fuel; the diesel oil / gas oil fraction, burned in diesel engines; the fuel oil fraction, used for marine vessels and domestic heating; the lubricating oil fraction, for lubricants, waxes and polishes; the bitumen fraction, for making roads
22.3Alkanes2 objectives
- State that alkanes are held together by single covalent bonds and belong to the group of saturated hydrocarbons
- Describe the properties of alkanes, which are unreactive in general except where combustion is concerned
22.4Alkenes7 objectives
- State that alkenes are unsaturated hydrocarbons, with a carbon–carbon double covalent bond as part of their bonding
- Describe how alkenes and hydrogen are produced by cracking large alkane molecules, which requires a high temperature and a catalyst
- Describe the reasons why large alkane molecules undergo cracking
- Describe the test that uses aqueous bromine to distinguish saturated from unsaturated hydrocarbons, based on how they react with it
- State that during an addition reaction, only a single product is obtained
- Describe how ethene forms poly(ethene) by addition polymerisation, and identify the repeat unit
- State that poly(ethene) is a plastic that is used widely
23.1Physical quantities and measurement techniques3 objectives
- Describe how to measure a range of lengths with tapes and rulers to a suitable precision, and be able to do so
- Describe the method, and show the skill, for measuring a liquid's volume with a measuring cylinder and finding a solid's volume through displacement
- Describe how clocks and digital timers are used to measure various time intervals, and carry out such measurements yourself
23.2Motion8 objectives
- Define speed as the distance covered in each unit of time
- State, then apply, the equation speed = distance / time
- State from memory the equation “average speed = total distance travelled / total time taken” and use it in calculations
- Define acceleration as how much the speed changes in each unit of time; also recall the equation “acceleration = change in speed / time taken” and use it
- Give the meaning of uniform acceleration and of non-uniform acceleration, and outline instances of each
- Sketch and plot distance–time and speed–time graphs, then interpret them
- Work out, from the shape of its distance–time graph, whether an object is accelerating, decelerating, moving at a constant speed or at rest
- Work out from a speed–time graph's shape whether an object has changing acceleration, has constant acceleration, has a constant speed or is at rest
23.3Mass and weight3 objectives
- describe the way an electronic balance is used to work out mass, and be able to carry out that determination
- describe the method by which weight is measured with a force meter, and be able to take that measurement
- define gravitational field strength as the force acting per unit of mass; recall and apply the relationship gravitational field strength = weight / mass, and know that it has the same value as the acceleration of free fall
23.4Density2 objectives
- Define density as the amount of mass contained in each unit of volume; recall and use the relationship density = mass / volume
- Describe how to find the density of: a liquid; a solid with a regular shape; a solid with an irregular shape that sinks in a liquid (finding its volume by displacement), including the calculations needed; and be able to do this
23.5.1Balanced and unbalanced forces4 objectives
- Identify and use the various kinds of force, including friction, drag, air resistance, contact force, weight (gravitational force), tension (elastic force), thrust (driving force), magnetic force and electrostatic force
- State that a force can alter how an object moves by altering its direction or its speed
- Work out the resultant when two or more forces lie along one straight line
- State from memory the equation “resultant force = mass × acceleration” and use it
23.5.2Friction1 objective
- Describe how friction, a force that might impede motion, can also generate heat
23.5.3Elastic deformation3 objectives
- Understand that forces can alter an object's dimensions and form.
- Define the spring constant: the force for each unit of extension; also recall “spring constant = force / extension” and use it
- Sketch, plot and interpret graphs of load against extension for a solid that is elastic, and describe the experiments used to obtain them
23.5.4Turning effect of forces3 objectives
- Describe the moment of a force as the size of its turning effect, and give examples of moments in everyday life
- Define the moment of a force through the equation “moment = force × perpendicular distance from the pivot”, and know this equation by heart and apply it
- Describe an experimental check of the principle of moments and carry one out
23.6.1Energy3 objectives
- Recall that energy can be held in the following stores: kinetic, gravitational potential, chemical, elastic (strain), nuclear, electrostatic and internal (thermal)
- Describe the way energy moves from one store to another in events and processes, including examples where it is transferred by forces (mechanical work done), by electrical currents (electrical work done), by heating, and by electromagnetic waves, sound waves and other waves
- Understand the principle of conservation of energy and use it when working through how energy shifts between stores in events and processes
23.6.2Work1 objective
- Recall and use the formula work done = force × distance, with the distance measured along the line in which the force acts
23.6.3Energy resources3 objectives
- Name the energy sources that are renewable, along with those that are non-renewable
- Describe how useful energy can be obtained, or electricity generated, from: wind, tides and sea waves; hydroelectric resources; solar radiation; geothermal resources; nuclear fuel; and the chemical energy stored in fossil fuels and in biofuels, including reference to any boiler, turbine and generator involved
- Give, for each method, its advantages and disadvantages, limited to: whether it is renewable, whether and when it is available, and its effect on the environment
24.1Kinetic particle model of matter1 objective
- Describe in words (qualitatively) how the particles are arranged in solids, liquids and gases, and relate the properties of each to the forces between the particles, the distances between them and the way the particles move (atoms, molecules, ions and electrons)
24.2Thermal expansion of solids, liquids and gases2 objectives
- Explain, using common examples, some applications and consequences of thermal expansion, including the liquid-in-glass thermometer
- Account for the thermal expansion of solids, liquids and gases by reference to how their particles move, how they are arranged and how far apart they are
24.3Transfer of thermal energy5 objectives
- Outline and carry out practical work that separates good thermal conductors from poor ones
- Account for convection in liquids and gases using changes in density, and outline experiments that show convection taking place
- Outline and carry out practical tests that tell apart good emitters of infrared radiation and poor ones
- Outline and carry out practical tests that tell apart good absorbers of infrared radiation and poor ones
- Account for everyday uses of conduction, convection and radiation, including: (a) heating objects such as kitchen pans (b) warming a room through convection (c) measuring temperature with an infrared thermometer (d) employing thermal insulation to keep a liquid at a steady temperature and to cut down on thermal energy transfer within buildings
25.1General properties of waves6 objectives
- Know that waves carry energy from one place to another without moving matter along with it
- Describe what wave motion means, using the examples of ropes and springs vibrating and of experiments with water waves
- Define these terms: (a) frequency – how many wavelengths pass a point in each unit of time (b) wavelength – the distance from one point on a wave to the next identical point, such as from one crest to the next (c) amplitude – the greatest distance measured from the mean position
- State from memory the equation “wave speed = frequency × wavelength”, v = f λ, and use it
- Know that in a transverse wave the vibrations are at right-angles to the way the energy is transferred, and give examples such as seismic S-waves (secondary), electromagnetic radiation and waves moving across the surface of water
- Know that in a longitudinal wave the vibrations are parallel to the way the energy is transferred, and give examples such as seismic P-waves (primary), sound waves, and the longitudinal waves in helical springs that are compressed, e.g. slinky toys
25.2.1Reflection of light3 objectives
- Define the normal, the angle of incidence and the angle of reflection, and use these terms
- Describe, and be capable of performing, experiments which make clear the law of reflection
- State that, in reflection, the angle of reflection is the same as the angle of incidence, and apply this to constructions, measurements and calculations
25.2.2Refraction of light2 objectives
- Define the words normal, angle of incidence and angle of refraction, and apply each one correctly
- Describe experiments showing how light is refracted by transparent blocks of various shapes, and be able to carry them out (refraction through lenses is not required)
25.3Electromagnetic spectrum3 objectives
- Know how the main regions of the electromagnetic spectrum are ordered by frequency and, separately, by wavelength
- Know that electromagnetic waves all share one speed: (a) in a vacuum it is 3.0 × 108 m/ s (b) in air it is approximately equal to the vacuum value
- Describe the role each of these regions plays in the applications given: (a) radio waves – communications by radio and television (b) microwaves – microwave ovens, Bluetooth and mobile (cell) phones (c) infrared – thermal imaging, remote controllers and household electrical appliances (d) visible light – vision and photography (e) ultraviolet – sterilising water and security marking (f) X-rays – medical imaging in hospitals, security scanners and killing cancerous cells (g) gamma rays – detecting and killing cancerous cells in medical treatment, sterilising medical equipment and food, and engineering uses such as detecting cracks in metal
26.1.1Electrical charge7 objectives
- State that charge occurs in positive and negative forms, and that its unit of measurement is the coulomb.
- State that two like charges push each other away (repel), while two unlike charges pull towards each other (attract)
- Describe, and carry out yourself, experiments that demonstrate electrostatic charging by friction.
- Explain that when solids are charged by friction, the only thing transferred is negative charge (electrons)
- Give instances of electrical conductors and of insulators.
- Describe examples of electrostatic charge causing problems, including lightning and the refuelling of aircraft
- Describe examples of electrostatic charge being useful, including spray painting, photocopiers and insecticide sprayers
26.1.2Electrical current3 objectives
- Define electric current as the charge that passes a point in each unit of time; also recall the equation “electric current = charge / time”, I = Q / t, and use it
- Describe electrical conduction in metals by reference to how free (delocalised) electrons move through the material
- Describe the way ammeters (analogue and digital) of differing ranges are employed, and be able to use them
26.1.3Potential difference2 objectives
- Describe how voltmeters, both analogue and digital, are employed, and be competent in operating them across different ranges
- Calculate the total voltage provided when several sources are connected in series
26.1.4Resistance3 objectives
- Recall and apply the formula resistance = p.d. / current R = V / I
- Describe an experiment in which a voltmeter and an ammeter are used to find resistance, and be capable of carrying it out along with the suitable calculations
- Calculate the combined resistance for a series arrangement of two or more resistors
26.2.1Circuit diagrams1 objective
- Draw and interpret circuit diagrams containing any of these components: cells, batteries and power supplies; switches and fuses; fixed and variable resistors, thermistors (NTC only) and light-dependent resistors (LDRs); diodes and light-emitting diodes (LEDS); heaters, lamps and motors; coils; ammeters and voltmeters
26.2.2Series and parallel circuits1 objective
- Recall these facts and use them in calculations: (a) a series circuit has the same current all the way round (b) where a parallel circuit has a junction, the currents flowing into it add up to the same total as the currents flowing out (c) across the components of a series circuit, the individual p.d.s add up to the total p.d. (d) for resistances connected in parallel, the p.d. across each branch matches the p.d. across the whole arrangement
26.3.1Uses of electricity4 objectives
- Name everyday jobs electricity does, including heating, lighting, battery charging and powering motors and electronic systems
- State from memory the equation “power = current × voltage”, P = IV, and use it
- State from memory the equation “energy = current × voltage × time”, E = IVt, and use it
- Define the kilowatt-hour (kWh), then work out what it costs to run electrical appliances where energy is given in kWh
26.3.2Electrical safety6 objectives
- State the hazards that come from: (a) insulation that is damaged (b) cables that overheat (c) damp conditions (d) excess current caused by overloading plugs, extension leads, single and multiple sockets on a mains supply
- Explain what trip switches and fuses are used for and how they operate, and choose suitable trip switch settings and fuse ratings
- Account for the sequence of events when a live wire makes contact with an earthed metal casing
- Account for why, in an electrical appliance, the exterior shell must be either earthed or non-conducting (double insulated)
- Understand that a mains circuit has three wires, namely the live (line) wire, the neutral wire and the earth wire, and explain why a switch needs to be placed in the live wire so the circuit can be switched off safely
- Account for the reason fuses and circuit breakers are placed in the live wire
27.1The nuclear model of the atom4 objectives
- Outline how an atom is built, with a positively charged nucleus at the centre and negatively charged electrons moving in orbits around it
- Outline what the nucleus is made of, using protons and neutrons
- Define (a) proton number/atomic number, Z and (b) nucleon number/mass number, A, and work out how many neutrons a nucleus holds
- Explain the meaning of isotope, and state that an element can possess more than one isotope
27.2.1Detection of radioactivity3 objectives
- Describe how alpha particles (α-particles) are detected with a cloud chamber or a spark counter, and how beta particles (β-particles) and gamma radiation (γ-radiation) are detected with a Geiger-Müller (GM) tube and counter; here β-particles means β−
- Use count rates, with units of either counts / s or counts /minute
- Understand the meaning of background radiation
27.2.2The three types of emission3 objectives
- Know that radioactive decay means an unstable nucleus undergoing a change which may lead to α, β and γ radiation being released, and know that such changes happen spontaneously and at random.
- Describe α-particles as made up of two protons plus two neutrons (helium nuclei), β-particles as fast-moving electrons emitted from the nucleus, and γ-radiation as electromagnetic waves of high frequency.
- State, for α-particles, β-particles and γ-radiation, (a) how each compares in its ionising effect (b) how each compares in its penetrating power
27.2.3Half-life and uses of radioactive isotopes2 objectives
- Define half-life, for a specific isotope, as the length of time it takes for half of that isotope's nuclei in any sample to undergo decay.
- Explain how the kind of radiation an isotope emits and its half-life decide which isotope is chosen for uses including: (a) household fire (smoke) alarms (b) killing bacteria in food by irradiation (c) sterilising equipment with gamma rays (d) measuring and controlling thickness, where the radiation chosen depends on penetration and absorption (e) diagnosing and treating cancer with gamma rays
27.2.4Safety precautions1 objective
- Explain the ways in which radioactive substances are transported, employed and kept in a safe manner, referring to: (a) shortening the length of time spent exposed (b) widening the gap between the source and living tissue (c) employing shielding to absorb radiation
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