AP®ChemistryCollege BoardExam QuestionsUnit 4: Chemical ReactionsTypes of Chemical Reactions

Types of Chemical Reactions (College Board AP® Chemistry)

Exam Questions

9 mins9 questions
11 mark

What is the oxidation number of Cr in Cr(H2O)63+?

  • 0

  • +1

  • +2

  • +3

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21 mark

Isooctane, shown below, can be added to fuels for improved performance.

Isooctane

Which is the correct equation for the complete combustion of isooctane?

  • C8H18 + 8½O2 → 8CO + 9H2O

  • C8H18 + 12½O2 → 8CO2 + 9H2O

  • C7H16 + 11O2 → 7CO2 + 8H2O

  • C8H18 + 13O2 → 8CO2 + 9H2O

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31 mark

Which of the following represents a redox reaction?

  • Fe + 2HCl → FeCl2 + H2

  • 2NH3 + HNO3 → NH4NO3

  • K2CO3 + 2CH3COOH → 2CH3COOK + CO2 + H2O 

  • ZnO + H2SO4 → ZnSO4 + H2O 

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41 mark

1 mol of a compound reacts with 9.5 mol of O2 for complete combustion. What is the formula of the compound?

  • C6H14

  • C6H13OH

  • C7H16

  • C7H15OH

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51 mark

3Cl2 (g) + 6NaOH (aq) → 5NaCl (aq) + NaClO3 (aq) + 3H2O (l)

Is the reaction represented above a redox reaction?

  • Yes, because chlorine is oxidized and oxygen is reduced.

  • Yes because chlorine is both oxidised and reduced.

  • Yes, because oxygen is oxidized and chlorine is reduced.

  • No, because none of the elements are oxidized or reduced.

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61 mark

3C2H5OH (l) + 2Cr2O72- (aq) + 16H+ → 3CH3COOH (l) + 4Cr3+ (aq) + 11H2O (l)

Which element is reduced in the above reaction and how does its oxidation number change?

  • Cr; its oxidation number changes from -2 to +3.

  • Cr; its oxidation number changes from +6 to +3.

  • O; its oxidation number changes from -1 to 0.

  • O; its oxidation number changes from +1 to -2.

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71 mark

H2SO4 (aq) + MgCO3 (s) → MgSO4 (aq) + H2O (l) + CO2 (g)

Which of the following is a correct description of the above reaction?

  • combustion

  • double replacement

  • neutralization with gas formation

  • single replacement

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81 mark

What is the formula of the precipitate formed when zinc nitrate reacts with sodium carbonate?

  • ZnCO3

  • Zn2CO3

  • Zn(CO3)2

  • Zn2(CO3)3

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91 mark
Diagram showing the reaction of aqueous copper(II) ions with sodium phosphate solution

Which of the following best describes the process represented above that takes place when Na3PO4 (aq) is added to CuCl2 (aq)?

  • It is a single replacement reaction in which copper replaces sodium in the Na3PO4.

  • It is an neutralization reaction in which the salt Cu3(PO4)2 is produced.

  • It is a precipitation reaction in which Cu3(PO4)2, an insoluble solid, is produced.

  • It is an oxidation-reduction reaction in which the oxidation number of Cl changes from −1 to 0 .

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