Multiple Choice Questions (MCQ) topic quiz

Developing Fuels

Instructions and answers for teachersThese instructions cover the learner activity section which can be found on page 9. This Lesson Element supports OCR AS and A Level Chemistry B (Salters).

When distributing the activity section to the learners either as a printed copy or as a Word file you will need to remove the teacher instructions section.

The ActivityThis Lesson Element is a teaching and learning resource containing 10 multiple choice questions (MCQs) on the theme of developing fuels. Some questions might require synoptic thinking, using knowledge and ideas from various topics across the full A Level content.

This resource can be used to test and consolidate understanding at the end of a topic or to revisit and refresh knowledge at a later point in the course.

Learning OutcomesThis lesson element relates to the specification learning outcomes DF(a), DF(d), DF(e), DF(g), DF(l), DF(m), DF(o), DF(q), DF(s), DF(t), DF(u).

IntroductionMultiple choice questions allow rapid coverage of a wide range of sub-topics.

Contrary to a widespread belief among students, multiple choice questions are not necessarily easy – they can be easy, moderate or difficult.

The questions are written so that the incorrect answers are plausible distractors based on common errors or misconceptions.

The questions in this quiz cover topics mainly from specification sections:

Developing fuels.

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Multiple Choice Questions (MCQ) topic quiz - answers1. Which molecule is a structural isomer of E-but-2-ene?

A Z-but-2-ene The learner has confused structural and geometric isomerism.

B 2-methylbut-2-ene The learner has not taken into account the extra carbon in the formula.

C methylpropane The learner has not taken into account different numbers of hydrogen atoms between alkanes and alkenes.

D methylpropene Correct answer: Methylpropene and Z-but-2-ene have the same molecular formula but different structure.

Your answer

2. Which statement must be true for an exothermic reaction?

A More bonds are broken than are made.

The learner has not appreciated that enthalpy change depends on bond energy rather than the number of bonds. They have also confused the relative sign of the enthalpy change for bond breaking vs making.

B More bonds are made than are broken.

The learner has not appreciated that enthalpy change depends on bond energy rather than the number of bonds.

C More energy is released in breaking bonds than is required to make bonds.

The learner has confused the relative sign of the enthalpy change for bond breaking vs making.

D More energy is released in making bonds than is required to break bonds.

Correct answer: Making bonds is exothermic and breaking bonds is endothermic.

Your answer

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D

D

3. Which reaction would have a negative value for H?

A CaCO3(s) CaO(s) + CO2(g) The reaction is a regularly used example of an endothermic process so the learner may be confused about the sign for an endothermic reaction.

B CaO(s) + H2O(l) Ca(OH)2(s) Correct answer: This is a vigorously exothermic reaction.

C 2H2O(l) 2H2(g) + O2(g) The learner may be thinking of the reverse process which is a well-known exothermic reaction.

D K(g) K+(g) + e– Ionisation enthalpy is always endothermic but some learners think of Group 1 metals as spontaneously forming positive ions so may mistake it for an exothermic process.

Your answer

4. What amount of gas takes up 6 dm3 at 102 kPa and 25 °C?

A 0.247 mol Correct answer: pV = nRT so n = pV/RT, where V is in m3, p is in Pa and T is in K.

B 2.94 mol The learner has not converted degrees Celsius to kelvin.

C 4.05 mol The learner has converted units correctly but has inverted the equation.

D 247 mol The learner has not converted dm3 into m3.

Your answer

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B

A

5. Which statement is true of the first step in the mechanism of the reaction between ethene and hydrogen bromide?

A The bromine atom accepts an electron pair from the carbon–carbon double bond.

This is true of the reaction between Br2 and ethene, but the HBr molecule has a permanent dipole meaning the hydrogen atom always accepts the electrons.

B The sigma bond between the two carbon atoms is broken.

The learner is confused about the nature of sigma and pi bonds, or may have the misconception that all bonds are broken initially (carried from the study of bond enthalpies in energetics).

C A bromide ion is formed. Correct answer: The bromine atom in HBr accepts the shared pair of electrons from the covalent bond in the first step.

D A carbon atom becomes negatively charged.

The learner is confused about the way charges form in this step of the mechanism.

Your answer

6. Which of these is an advantage of using biodiesel as a substitute for petrol?

A It is a renewable resource. Correct answer: Biodiesel is made from plants which can be regrown.

B No CO2 is released on combustion.

A common misconception stemming from the description of biofuels as ‘carbon neutral’.

C It has a higher energy density. Another common assumption which is not true; biodiesel produces less energy per gram.

D Less NOx is released on combustion.

A misconception stemming from the idea of biodiesel being a ‘clean’ fuel, without taking into account the nature of the engine as the comparison is being made with petrol and not regular diesel.

Your answer

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C

A

7. The alkenes are an example of a homologous series of compounds.

Which statement is true for all members of any homologous series?

A They all have the same molecular formula.

The learner is perhaps confusing molecular and general formulae.

B They all have the same general formula.

Correct answer: Each member of a homologous series differs by one CH2 group.

C They all have the same physical properties.

The learner is perhaps confusing physical with chemical properties or is thinking of physical trends (e.g. increasing boiling points).

D They all react with bromine water. The learner has misread the question, which refers to any homologous series, as referring to alkenes.

Your answer

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B

8. A Hess cycle is shown below.

What is a correct expression for H1 constructed using the Hess cycle shown?

A fH(C2H5OH) – [fH(CH2CH2) + fH(H2O)]

The learner has not paid attention to the direction of the arrows in the Hess cycle or to the substances at the bottom which clearly show the products of combustion and not elements.

B [fH(CH2CH2) + fH(H2O)] – fH(C2H5OH)

The learner has paid attention to the direction of the arrows but not to the fact that these are enthalpies of combustion rather than formation (see above).

C cH(CH2CH2) – cH(C2H5OH) Correct answer: Water does not have an enthalpy of combustion as it is a product of combustion.

D cH(C2H5OH) – cH(CH2CH2) The learner has appreciated that combustion enthalpies need to be used but has rearranged the components of the Hess cycle incorrectly from the direction of the arrows given.

Your answer

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C

9. What is the correct name for the compound shown below?

A Z-but-2-ene The learner has miscounted the number of atoms in the chain.

B E-1-methyl-2-ethylethene The learner has not appreciated the importance of the longest carbon chain in systematic names, and also has E/Z isomers confused.

C Z-1-methyl-2-ethylethene The learner has not appreciated the importance of the longest carbon chain in systematic names.

D Z-pent-2-ene Correct answer: The molecule has a five-carbon chain and the hydrogen atoms are on the same side of the double bond.

Your answer

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D

10. Three flasks each contain 240 cm3 of a different gas, under the same conditions of room temperature and pressure.

Which of the following statements is/are true for all three of the flasks?

1. They each contain the same number of gas molecules.

2. They each contain 0.1 mol of gas.

3. They each contain the same number of atoms.

A 1, 2 and 3 Statement 1 is correct. Statement 2 is incorrect and the learner has either leapt to conclusions or rushed the calculation; the flasks contain 0.01 mol of gas. For Statement 3, the learner has not appreciated the range of different sizes and formulae of gas molecules.

B only 1 and 2 The learner understands that different gas molecules can contain different numbers of atoms, but has rushed the volume/amount calculation.

C only 2 and 3 The learner has omitted the only correct answer and may have misread the question.

D only 1 Correct answer: Only the first statement is correct – the amount of gas, and therefore number of individual gas molecules, will be the same.

Your answer

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D

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Multiple Choice Questions (MCQ) topic quiz

Developing Fuels

Learner Activity

1. Which molecule is a structural isomer of E-but-2-ene?

A Z-but-2-ene

B 2-methylbut-2-ene

C methylpropane

D methylpropene

Your answer

2. Which statement must be true for an exothermic reaction?

A More bonds are broken than are made.

B More bonds are made than are broken.

C More energy is released in breaking bonds than is required to make bonds.

D More energy is released in making bonds than is required to break bonds.

Your answer

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3. Which reaction would have a negative value for H?

A CaCO3(s) CaO(s) + CO2(g)

B CaO(s) + H2O(l) Ca(OH)2(s)

C 2H2O(l) 2H2(g) + O2(g)

D K(g) K+(g) + e–

Your answer

4. What amount of gas takes up 6 dm3 at 102 kPa and 25 °C?

A 0.247 mol

B 2.94 mol

C 4.05 mol

D 247 mol

Your answer

5. Which statement is true of the first step in the mechanism of the reaction between ethene and hydrogen bromide?

A The bromine atom accepts an electron pair from the carbon–carbon double bond.

B The sigma bond between the two carbon atoms is broken.

C A bromide ion is formed.

D A carbon atom becomes negatively charged.

Your answer

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6. Which of these is an advantage of using biodiesel as a substitute for petrol?

A It is a renewable resource.

B No CO2 is released on combustion.

C It has a higher energy density.

D Less NOx is released on combustion.

Your answer

7. The alkenes are an example of a homologous series of compounds.

Which statement is true for all members of any homologous series?

A They all have the same molecular formula.

B They all have the same general formula.

C They all have the same physical properties.

D They all react with bromine water.

Your answer

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8. A Hess cycle is shown below.

What is a correct expression for H1 constructed using the Hess cycle shown?

A fH(C2H5OH) – [fH(CH2CH2) + fH(H2O)]

B [fH(CH2CH2) + fH(H2O)] – fH(C2H5OH)

C cH(CH2CH2) – cH(C2H5OH)

D cH(C2H5OH) – cH(CH2CH2)

Your answer

9. What is the correct name for the compound shown below?

A Z-but-2-ene

B E-1-methyl-2-ethylethene

C Z-1-methyl-2-ethylethene

D Z-pent-2-ene

Your answer

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10. Three flasks each contain 240 cm3 of a different gas, under the same conditions of room temperature and pressure.

Which of the following statements is/are true for all three of the flasks?

1: They each contain the same number of gas molecules.

2: They each contain 0.1 mol of gas.

3: They each contain the same number of atoms.

A 1, 2 and 3

B only 1 and 2

C only 2 and 3

D only 1

Your answer

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