Understanding of chemical changes began when people began experimenting with chemical reactions in a systematic way and organising their results logically. Knowing about these different chemical changes meant that scientists could begin to predict exactly what new substances would be formed and use this knowledge to develop a wide range of different materials and processes. It also helped biochemists to understand the complex reactions that take place in living organisms. The extraction of important resources from the Earth makes use of the way that some elements and compounds react with each other and how easily they can be ‘pulled apart’.
There will be an end of topic assessment using past exam questions to be completed under exam conditions and assessed by the teacher.
Atom
The smallest particle of a chemical element that can exist.
Bond
Join or be joined securely to something else, especially by means of an adhesive substance, heat, or pressure; join or be joined by a chemical bond.
Chemical
Chemistry is a branch of physical science that studies the composition, structure, properties and change of matter.
Collisions
Particles colliding against each other
Covalent
Relating to or denoting chemical bonds formed by the sharing of electrons between atoms.
Cracking
In petroleum geology and chemistry, cracking is the process whereby complex organic molecules such as kerogens or long chain hydrocarbons are broken down into simpler molecules such as light hydrocarbons.
Particle
A minute portion of matter.
Physical
In a physics reaction the reaction is reversible
Polymerisation
A chemical process that combines several monomers to form a polymer or polymeric compound.
Rate
A certain quantity or amount of one thing considered in relation to a unit of another thing and used as a standard or measure
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Students will consider that energy changes are an important part of chemical reactions. The interaction of particles often involves transfers of energy due to the breaking and formation of bonds. Reactions in which energy is released to the surroundings are exothermic reactions, while those that take in thermal energy are endothermic. Some interactions between ions in an electrolyte result in the production of electricity. Electricity can also be used to decompose ionic substances and is a useful means of producing elements that are too expensive to extract any other way.
There will be an end of topic assessment using past exam questions to be completed under exam conditions and assessed by the teacher.
Electrolysis
The process of splitting up an ionic compound using electricity
Anode
A positive electrode
Cathode
A negative electrode
Reduction
Gain of electrons
Oxidation
Loss of electrons
Exothermic
a reaction that transfers energy to the surroundings
activation energy
the minimum energy needed for a reaction to take place
bond energy
the energy required to break a specific chemical bond
endothermic
a reaction that takes in energy from the surroundings
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Students will investigate how Chemical reactions can occur at vastly different rates. Many variables that can be manipulated in order to speed them up or slow them down. Chemical reactions may also be reversible and therefore the effect of different variables needs to be established in order to identify how to maximise the yield of desired product.
Analysts have developed a range of qualitative tests to detect specific chemicals. The tests are based on reactions that produce a gas with distinctive properties, or a colour change or an insoluble solid that appears as a precipitate. Instrumental methods provide fast, sensitive and accurate means of analysing chemicals, and are particularly useful when the amount of chemical being analysed is small. Forensic scientists and drug control scientists rely on such instrumental methods in their work.
There will be an end of topic assessment using past exam questions to be completed under exam conditions and assessed by the teacher.
activation energy
the minimum energy needed for a reaction to take place
bond energy
the energy required to break a specific chemical bond
endothermic
a reaction that takes in energy from the surroundings
exothermic
a reaction that transfers energy to the surroundings
fuel cells
sources of electricity that are supplied by an external source of fuel
pipette
a glass tube used to measure accurate volumes of liquids
Rf (retention factor)
a measurement from chromatography: it is the distance a spot of substance has been carried above the baseline divided by the distance of the solvent front
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In this topic we will look at how Chemists use quantitative analysis to determine the formulae of compounds and the equations for reactions. Identifying different types of chemical reaction allows chemists to make sense of how different chemicals react together, to establish patterns and to make predictions about the behaviour of other chemicals.
There will be an end of term assessment using past exam questions to be completed under exam conditions and assessed by the teacher.
Avogadro constant
the number of atoms, molecules, or ions in a mole of any substance (i.e., 6.02 × 10-23 per mol)
burette
a long glass tube with a tap at one end and markings to show volumes of liquid; used to add precisely known volumes of liquids to a solution in a conical flask below it
concentration
the amount of a substance dissolved in a given volume of liquid
limiting reactant
the reactant in a chemical reaction that when used up causes the reaction to stop
mole
the amount of substance in the relative atomic or formula mass of a substance in grams
percentage yield
the actual mass of product collected in a reaction divided by the maximum mass that could have been formed in theory, multiplied by 100
relative atomic mass Ar
the average mass of the atoms of an element compared with carbon-12 (which is given a mass of exactly 12). The average mass must take into account the proportions of the naturally occurring isotopes of the element
relative formula mass Mr
the total of the relative atomic masses, added up in the ratio shown in the chemical formula, of a substance
yield
the mass of product that a chemical reaction produces
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Pupils will review all learning from Year 9 and 10 in science to complete their end of year exams. This will entail a lot of intensive revision time and personal analysis before returning in Year 11.
The 3 exams will be a set of past exam questions with around 100 marks available in each paper at either a Higher or a Foundation level. They should aim to answer one mark per minute. The questions will be a mixture of short answer and long answer questions, each worth 1-6 marks. Pupils we be expected to recall knowledge, describe and explain theories, complete calculations using memorised equations and apply their understanding to previously unknown data or scenarios.
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Industries use the Earth’s natural resources to manufacture useful products. In order to operate
sustainably, chemists seek to minimise the use of limited resources, use of energy, waste and
environmental impact in the manufacture of these products. Chemists also aim to develop ways of
disposing of products at the end of their useful life in ways that ensure that materials and stored
energy are utilised. Pollution, disposal of waste products and changing land use has a significant
effect on the environment, and environmental chemists study how human activity has affected the
Earth’s natural cycles, and how damaging effects can be minimised.
End of topic assessment using past paper questions
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