| formula equation for fermentation | C6H12O6 (aq) ————> 2C2H5OH (aq) + 2CO2(g) + 2ATP |
| formula for acid reaction | 2HCl + Mg → MgCl2 + H2 |
| reaction of acids (sulphuric acid) with carbonates (sodium carbonate) | NaCO3 + H2SO4 → NaSO4 + H2O + CO2 |
| ionic neutralisation reaction | H+(aq)+OH–(aq)⟶ H2O (l) |
| preparation of insoluble salts by precipitation | mixing two soluble salts in a solution, which react to form an insoluble salt that precipitates, or falls out of the solution |
| acid base titration apparatus | 25 cm3 volumetric pipette, 50 cm3 burette |
| how to find the end-point of a titration using an indicator | the point at which the indicator changes colour |
| why carbon anodes need to be replaced | the graphite carbon anode reacts with the oxygen produced, resulting in them being burnt away over time |
| acids proton/neutron giving | acids are proton donors |
| what structure is this | ethanoic acid |
| what structure is this | methane |
| what structure is this | ethene |
| what structure is this | ethanoic acid |
| functional group for alcohols | -O-H |
| draw the functional group for a carboxylic acid | ummmm yay |
| draw the functional group of amine | ummmm yay |
| draw the functional group for an ester | ummmm yay |
| hydrocarbon | compounds made up of only carbon and hydrogen bonded together |
| what do carboxylic acids end in | oic acid |
| what do alcohols end in | ol |
| 3 fossil fuels | oil, natural gas, petroleum |
| main thing in natural gas | methane |
| what is petrol made up from | hydrocarbons |
| general characteristics of a homologous series | having the same general formula, same functional group, differing from one member to the next by a -CH2- unit, sharing similar chemical properties, displaying a trend in physical properties. |
| functional group | an atom or group of atoms that determine the chemical properties of a homologous series |
| structural formula | an unambiguous description of the away atoms in a molecule are arranged, e.g. CH2=CH2 |
| structural isomers | compounds with the same molecular formula but different structural formula |
| alkanes reactivity | generally unreactive except with combustion and chlorine |
| general formula of alkanes | CnH2n+2 |
| saturated and example | molecules in which all carbon-carbon bonds are single, alkanes |
| unsaturated and example | molecules with one or more carbon-carbon bonds that are not single bonds, alkenes |
| complete combustion | reacts with excess oxygen to produce CO2 and H2O |
| incomplete combustion | reacts with limited oxygen to produce either carbon monoxide and H2O or carbon and H2O |
| what happens in a substitution reaction | one atom or groups of atoms is replaced by another atom or group of atoms, like alkanes and bromine |
| general formula of alkenes | CnH2n |
| what kind of bonds do alkenes have | one or more carbon-carbon double covalent bonds |
| how are alkenes formed | in the cracking of larger alkane molecules, hydrogen can form it as well but it needs high temp and catalyst |
| reasons for cracking | create more useful substances |
| thermal cracking | high temperature and pressure |
| catalytic cracking | low temperature and pressure, catalyst |
| addition reaction | only one product is formed, like reactions of alkenes and bromine |
| how to make an alcohol | Alkenes react with steam to produce an alcohol. This time, it is the hydrogen and the hydroxide from water that adds across the double bond. An acid catalyst is needed, 300oC and 60atm (6000kPa) pressure |
| how to make alkanes from alkenes | react with hydrogen at 150C with nickel catalyst |
| product of alkene and bromine water | dibromoalkane |
| how is polyethene made | alkenes can be used to make polymers by joining together in long chains, the product is called an addition polymer |
| how is ethanol made | by fermentation using aqueous glucose and yeast in the absence of oxygen at 25-35C |
| word equation for fermentation | glucose (enzymes) (in yeast) → ethanol + carbon dioxide |
| symbol equation for fermentation | C6H1206 → 2CH3CH20H+2CO2 |
| how is pure ethanol extracted | fractional distillation |
| ethanol with combustion/burn with oxygen | react in the same way as alkanes, complete combustion |
| general formula of alcohols | CnH2n+1OH |
| what is ethanol used for | fuel and as a solvent |
| general formula for carboxylic acid | CnH2n+1COOH |
| ethanoic acid reactions | is a weak acid and will undergo reactions that other acids do with metals, carbonates and bases |
| acid + metal | salt + hydrogen |
| acid + base | (neutralization) salt + water |
| acid + carbonate | salt + water + carbon dioxide |
| how is ethanoic acid formed | the oxidation of ethanol using bacterial oxidation during vinegar production or acidified potassium permanganate |
| carboxylic acid + alcohol | will produce an ester, sulphuric acid acts as a catalyst and a dehydrating agent |
| substitution reaction with chlorine and alkanes | alkanes react with chlorine to form substituted alkanes in the presence of UV light, proving the activation energy (photochemical reaction). This is a substitution reaction as a chlorine replaces one hydrogen |
| formula equation for fermentation | C6H12O6 (aq) → 2C2H5OH (aq) + 2CO2(g) + 2ATP |
| advantage of using fractional distillation to make ethanol | high purity, cheaper, easier access to resources |
| disadvantage of using fractional distillation to make ethanol | product impure, slow |
| advantage of hydration of ethene | product is pure, fast |
| disadvantage of hydration of ethene | made from non-renewable sources, lots of energy needed |
| fractionating column | refinery gas, gasoline, naptha, kerosene/paraffin, diesel oil/gas oil, fuel oil, lubricating oil, bitumen |
| use of refinery gas | gas used in heating and cooking |
| use of gasoline | as fuel in cars |
| use of naptha | a chemical feedstock |
| use of kerosene | jet fuel |
| use of diesel oil | fraction for fuel in diesel engines |
| use of fuel oil | fuel used in ships and home heating systems |
| use of lubricating oil | lubricants and waxes and polishes |
| use of bitumen | making roads |
| from top to bottom of the fractionating column how does chain length change | increases |
| from top to bottom of the fractionating column how does volatility change | decreases |
| from top to bottom of the fractionating column how does the boiling point change | increases |
| from top to bottom of the fractionating column how does viscosity change | increases |
| polymers | large molecules built up from many smaller molecules called monomers |
| what everyday substance is made from polymers | plastics which are not biodegradable and cannot be recycled so has implications for disposal |
| the environmental challenges caused by plastics | disposal in land fill sites, accumulation in oceans, formation of toxic gases from burning |
| what is the general structure of amino acids | general structure of amino acids |
| polymer of this monomer | polymer |
| polymer of this monomer | polymer |
| oxidation | the gain of oxygen but the loss of electrons |
| reduction | the loss of oxygen but the gain of electrons |
| oxidising agent | a substance that oxidises another substance and is itself reduced |
| reducing agent | a substance that reduces another substance and is itself oxidised |
| electrolysis | the decomposition of an ionic compound when in molten or aqueous by the passage of electric current |
| what are electrodes made from | unreactive (inert) metals or graphite and are used to conduct electricity |
| cathode | is the negative electrode |
| anode | is the positive electrode |
| what is formed at the negative electrode | metals or hydrogen |
| what is formed at the positive electrode | non-metals |
| why are metal objects are electroplated | to improve their appearance and resistance to corrosion |
| if there is a non-metal in electrolysis, what charge does it have | negative |
| if there is a metal in electrolysis, what charge does it have | positive |
| oxidation number rules | - oxidation number of oxygen in a compound is -2
- oxidation number of hydrogen in a compound is +1
- the sum of oxidation numbers in a compound or molecule = zero
- oxidation number of a monatomic ion = the charge on the ion
- the sum of oxidation numbers of polyatomic ion = the charge on the ion
- the oxidation number of an element = zero. |
| electrolysis flow chart | electrolysis flow chart |
| metals that are less reactive than hydrogen and will be shown at the cathode | copper, gold, platinum |
| describe the transfer of charge during electrolysis | during electrolysis, ions in the electrolyte move towards the electrodes: cations move to the cathode (negative electrode) and gain electrons (reduction), while anions move to the anode (positive electrode) and lose electrons (oxidation). Electrons flow through the external circuit from the power source's negative terminal to the cathode and from the anode to the power source's positive terminal |
| what is the main ore of aluminium | bauxite |
| how is aluminium extracted | bauxite is purified to get aluminium oxide then aluminium is extracted by electrolysis |
| uses of cryolite | aluminium oxide is dissolved in molten cryolite, lower the melting point and saves money |
| why do carbon electrodes need to be replaced regularly | they react with the oxygen produced during the electrolysis to form CO2 and get eaten away |
| equation at the cathode for extraction of aluminium | Al3+ + 3e- → Al |
| equation at the anode for extraction of aluminium | O2- → O +2e- |
| how do hydrogen-oxygen fuel cells work | they use hydrogen and oxygen to produce electricity with water as the only product |
| advantages of fuel cells | require only hydrogen and oxygen, don't produce any waste, last longer than batteries, less polluting to dissolve of |
| disadvantage of fuel cells | hydrogen is a gas, more space to store than fossil fuels or batteries, explosive when mixed with air, storage is dangerous, requires energy often coming from fossil fuels |
| rate of reaction | the number of particles per unit time that collide |
| Describe and draw nylon (polyamide) | proteins are natural polyamides formed from amino acid |
| what can rate of reaction be determined by | measuring the volume of gas in a gas syringe or an upturned measuring cylinder or burette full of water over time, loss of mass of a gas over time, timing how long a precipitate takes to form, to cover the cross. How fast the reactants are being used, how fast the products are being formed |
| describe and draw PET (polyester) | can be converted back into monomers and re-polymerised |
| rate of reaction equation | quantity of reactants used/time taken, quantity of products formed/time taken |
| the factors that affect the rate of a chemical reaction | increasing the temperature increases the rate, increasing the concentration of one or more of the reactants increases the rate, decreasing the particle size of a solid reactant increases the rate, use of enzymes/catalysts |
| collision theory | reactions occur because particles collide and have enough kinetic energy |
| why do explosions happen in flour mills or mines | fine particles of readily combustible flour in the air or explosive combinations of gases |
| what does increasing the concentration do | increases the number of particles per volume so increases the frequency of collisions between particles so increases the rate |
| what does increasing the temperature do on gas | increases the volume of a gas |
| what does increasing the temperature do on particles | increases the kinetic energy of the particles so they move faster. This increases the frequency of collisions between particles, so more particles have energy above the activation energy, so increases the rate |
| what does increasing the pressure do | decreases the volume of a gas and increases the number of effective collisions, increasing the rate |
| what does increasing the surface area do | increases the frequency of collisions between particles, so increases the rate |
| what does adding a catalyst do | increases the rate as it decreases the activation energy of a reaction. The reverse occurs if you remove a catalyst |
| difference between addition and condensation polymers | condensation polymers produce water as well, condensation polymers are biodegradable unlike addition polymers |
| draw the general structure of amino acids | general structure of amino acids |
| how to identify amino acids | chromatography can be used to separate and identify them using Rf values, Rf = distance spot travels/distance solvent front travels |
| describe and draw the structure of proteins | structure of protein |
| mass of a reactant | moles x Mr |
| avogadros constant | 6.02 × 10²³ |
| percentage yield | actual yield/theoretical yield x 100 |
| concentration calculation | moles/volume |
| exothermic reactions - temperature | those transferring (giving out) thermal energy so the temperature of the surroundings goes up |
| exothermic reactions - energy | energy is released when bonds are formed |
| endothermic reactions - temperature | require (take in) thermal energy- the temperature of the surroundings goes down |
| endothermic reactions - energy | energy is absorbed when bonds are broken |
| enthalpy change | the transfer of thermal energy during a reaction is called the enthalpy change |
| ΔH | negative for exothermic reactions and positive for endothermic reactions |
| activation energy | the minimum energy that colliding particles must have to react |
| reversible reaction symbol | ⇌ |
| how are reversible reactions reversed | reversible reactions can be reversed by changing the reaction conditions |
| how is a hydrated salt formed | when water is added back to an anhydrous salt |
| how is water removed - hydrated salts | when a hydrated salt is gently heated, often leaving condensation on the top of the test tube |
| IDEK | Know that a reversible reaction in a closed system is at equilibrium when the rate of the forward reaction is equal to the rate of the reverse with the concentrations of products and reactants are no longer changing |
| effect of changing pressure on equilibrium | an increase in pressure pushes the equilibrium in favour of the side of the equations with the lower number of moles of gas |
| effect of increasing temperature on equilibrium | increasing temperature favours the endothermic direction |
| effect of changing concentration on equilibrium | changing the concentration goes to the side that opposes the change |
| effect of catalyst on position of equilibrium | doesn't change it |
| equation to produce ammonia | N2(g) + 3H2(g) ⇌ NH3(g) |
| where does the nitrogen come from in the production of ammonia (Haber process) | the air |
| where does the hydrogen come from in the production of ammonia (Haber process) | hydrocarbons |
| temperature required for the Haber process | 450oc |
| pressure required for the Haber process | 200 atm |
| catalyst for the Haber process | Fe |
| equation for the conversion of sulphur dioxide to trioxide in the Contact process | 2 SO2 + O2 ⇌ 2SO3 |
| reaction pathway endothermic | reaction pathway endothermic |
| reaction pathway exothermic | reaction pathway exothermic |
| what do hydrogen oxygen fuel cells use | hydrogen and oxygen to produce electricity with water as the only product |
| advantages of hydrogen oxygen fuel cells | hydrogen can be produced from water so the process is renewable, they do not produce any pollution: the only product is water whereas petrol engines produce carbon dioxide, and oxides of nitrogen, they release more energy per kilogram than either petrol or diesel |
| disadvantages of hydrogen oxygen fuel cells | - materials used in producing fuel cells are expensive
- fuel cells are affected by low temperatures, becoming less efficient
- there are only few hydrogen filling stations across the country |
| difference between fractional distillation and simple distillation | fractional distillation is used when the components have close boiling points, and simple distillation is used when the boiling points are significantly different |
| raw materials of iron | coke/carbon, iron(III) oxide, limestone which removes acidic impurities |
