Developing Fuels | OCR A-Level Chemistry B (Salters) (H433)

Developing Fuels

364 questions
24 subtopics
The ten storylines, examined across all three papers
Component 01, Component 02 and Component 03

The storyline that carries thermochemistry and the first organic chemistry: gas volumes and the ideal gas equation, enthalpy changes and how they are measured, bond enthalpies and Hess' law, catalysis and cracking, the pollutants from burning fuels, and the alkanes, alkenes and polymers..

It covers molar gas volume and the ideal gas equation, gas volume calculations and measuring a gas in the laboratory, bonding and shape in organic molecules, enthalpy changes: definitions and standard conditions, bond enthalpies, q = mcΔT and measuring an enthalpy change in solution, burning a fuel, correcting for heat loss, and the assumptions made, hess' law and enthalpy cycles, catalysts, heterogeneous catalysis and catalyst poisons, cracking and how it is carried out, the pollutants from burning fuels and their effects, catalytic converters and cutting emissions, aliphatic and aromatic compounds, functional groups and general formulae, deducing formulae and naming a branched compound, combustion of organic compounds, addition of bromine and hydrogen halides, and the test for unsaturation, hydrogenation and hydration of alkenes, addition polymerisation, electrophilic addition mechanism, displayed, shortened and skeletal formulae, chain, position and functional group isomerism, why alkenes show stereoisomerism, and the E/Z and cis/trans rules, naming and comparing the stereoisomers and sustainable fuels: benefits and risks.

Sample questions from Developing Fuels

Answer each one closed book first, then open the answer.

Molar gas volume and the ideal gas equation

What amount of gas, in moles, is present in 720 cm³ of oxygen at RTP?

Show the answer
720 cm³ is 0.720 dm³, so the amount is 0.720 ÷ 24.0 = 0.0300 mol.
Enthalpy changes: definitions and standard conditions

Why is an enthalpy change of combustion always negative?

Show the answer
Burning always releases energy to the surroundings, so the value can never be positive.
Burning a fuel, correcting for heat loss, and the assumptions made

Apart from heat loss, give a source of error when burning a volatile fuel.

Show the answer
Some of the fuel evaporates without burning, so the loss in mass overstates the amount actually burned.
Cracking and how it is carried out

Write an equation for the cracking of decane into octane and one other product.

Show the answer
C₁₀H₂₂ → C₈H₁₈ + C₂H₄.
Aliphatic and aromatic compounds, functional groups and general formulae

Give the molecular formula of benzene.

Show the answer
Benzene is C₆H₆.
Addition of bromine and hydrogen halides, and the test for unsaturation

Name the product formed when bromine adds to ethene.

Show the answer
It is 1,2-dibromoethane.
Electrophilic addition mechanism

Describe the first step in the addition of hydrogen bromide to ethene.

Show the answer
The π electrons of the double bond are attracted to the δ+ hydrogen of the polar H–Br molecule; a curly arrow from the double bond to that hydrogen forms a C–H bond, while a second curly arrow from the H–Br bond to the bromine releases a bromide ion.
Why alkenes show stereoisomerism, and the E/Z and cis/trans rules

Why does but-1-ene show no stereoisomerism?

Show the answer
One carbon of its double bond carries two hydrogen atoms, so exchanging them gives back the same molecule.

The 24 subtopics

One subtopic is one session. Work down the list.

Subtopic	What it covers	Questions
Molar gas volume and the ideal gas equation	Recall questions on molar gas volume at RTP, the ideal gas equation and the gas constant, and the units each quantity must be in.	12
Gas volume calculations and measuring a gas in the laboratory	Recall questions on finding a volume or an amount from pV = nRT, reading volume ratios off an equation, and why a measured volume comes out low.	12
Bonding and shape in organic molecules	Recall questions on sigma and pi bonding, why rotation is free about C-C but not C=C, and the bond angles around a saturated and an unsaturated carbon.	20
Enthalpy changes: definitions and standard conditions	Recall questions on exothermic and endothermic changes, standard conditions and standard states, and the definitions of the standard enthalpy changes.	22
Bond enthalpies	Recall questions on why bond enthalpies are averages, whether breaking and making release or absorb energy, and calculating ΔH from them.	21
q = mcΔT and measuring an enthalpy change in solution	Recall questions on q = mcΔT and what each symbol means, and on measuring an enthalpy change in a polystyrene cup.	9
Burning a fuel, correcting for heat loss, and the assumptions made	Recall questions on the burning-fuel calorimeter, why the result is less exothermic than the data book value, and correcting by extrapolation.	15
Hess' law and enthalpy cycles	Recall questions on why an indirect route gives the same answer, building a cycle from combustion or formation data, and checking it has been used correctly.	21
Catalysts, heterogeneous catalysis and catalyst poisons	Recall questions on how a catalyst works, adsorption, reaction and desorption on a surface, and why a poisoned catalyst is an economic problem.	16
Cracking and how it is carried out	Recall questions on why cracking matters to the oil industry, why a product must be unsaturated, and how a hydrocarbon is cracked in the laboratory.	9
The pollutants from burning fuels and their effects	Recall questions on particulates, unburnt hydrocarbons, carbon monoxide and the oxides of nitrogen and sulfur, and the effects of each.	17
Catalytic converters and cutting emissions	Recall questions on what a catalytic converter removes and how, why it works poorly when cold, and how sulfur dioxide is removed from flue gas.	8
Aliphatic and aromatic compounds, functional groups and general formulae	Recall questions on aliphatic, aromatic and arene, saturation, functional groups and homologous series, and the general formulae.	16
Deducing formulae and naming a branched compound	Recall questions on deducing a molecular formula from a general one, the stems for one to ten carbons, and choosing and numbering the main chain.	10
Combustion of organic compounds	Recall questions on the conditions for complete combustion, the extra products when it is incomplete, and writing balanced combustion equations.	22
Addition of bromine and hydrogen halides, and the test for unsaturation	Recall questions on why a C=C bond is reactive, the bromine water test and what it shows, and the products with a hydrogen halide.	12
Hydrogenation and hydration of alkenes	Recall questions on the conditions for hydrogenation and why nickel is used industrially, and on the two routes from ethene to ethanol.	12
Addition polymerisation	Recall questions on monomers and repeat units, deducing one from the other, and naming the common addition polymers.	20
Electrophilic addition mechanism	Recall questions on what an electrophile is, the steps by which hydrogen bromide adds to ethene, and the intermediate formed.	22
Displayed, shortened and skeletal formulae	Recall questions on what each kind of formula shows, reading a skeletal formula, and choosing which to use.	9
Chain, position and functional group isomerism	Recall questions on the three kinds of structural isomerism and on listing the isomers of a given molecular formula.	14
Why alkenes show stereoisomerism, and the E/Z and cis/trans rules	Recall questions on why there is no rotation about C=C, the condition for stereoisomerism, and the E/Z priority rules.	14
Naming and comparing the stereoisomers	Recall questions on naming the stereoisomers of but-2-ene and 1,2-dichloroethene, and why their melting and boiling points differ.	9
Sustainable fuels: benefits and risks	Recall questions on biofuels and alternative fuels, carbon neutrality, and weighing the benefits of a fuel against its risks.	22

Developing Fuels is 364 of the 3,430 questions in the guide.Get the guide, £8

How the guide is worked

Answering a question from memory stores it far better than reading the answer again. The guide runs that as a fixed procedure on one subtopic at a time, about twenty minutes a session.

Step 1 · Closed book
Cover the answers. Work through one subtopic and write down what you can. Leave blanks where you have nothing.
Step 2 · Open book
Go back to the top. Read each printed answer and write it out in full, including the ones you had right.
Step 3 · Closed book again
Same questions, same order, from memory. The gap between pass one and pass three is the session result.

Read the full method, the return schedule and the research behind it.