10-minute Quiz : Chapter 36 Rate of chemical reaction

A student used the set-up shown in the diagram to study the rate of a reaction at 25°C. Which of the following reactions is likely to be studied by that student?

• A. CaO + H₂SO₄ → CaSO₄ + H₂O
• B. Mg(OH)₂ + 2HCl → MgCl₂ + 2H₂O
• C. Fe + H₂SO₄ → FeSO₄ + H₂
• D. KCl + AgNO₃ → KNO₃ + AgCl

Which of the following chemical reactions is the fastest at room temperature?

• A. 4Ag(s) + O₂(g) → 2Ag₂O(s)
• B. 2H₂O₂(aq) → 2H₂O(l) + O₂(g)
• C. Ca(OH)₂(aq) + CO₂(g) → CaCO₃(s) + H₂O(l)
• D. Na₂S₂O₃(aq) + 2HCl(aq) → S(s) + SO₂(aq) + H₂O(l) + 2NaCl(aq)

Consider the reaction between magnesium and dilute hydrochloric acid at a certain temperature:

Mg(s) + 2HCl(aq) → MgCl₂(aq) + H₂(g)

If 1.22 g of magnesium completely reacted with the acid in 10 seconds, what would be the average rate of consumption of magnesium over this time interval at that temperature?

(Relative atomic mass: Mg = 24.3)

• A. 2.9 mol s⁻¹
• B. 2.0 mol s⁻¹
• C. 0.05 mol s⁻¹
• D. 0.005 mol s⁻¹

In an experiment, a student added a few lumps of calcium carbonate to excess dilute nitric acid and recorded the volume of carbon dioxide evolved at 2-minute intervals until all calcium carbonate had reacted. The results are shown in the graph. At what time interval was the reaction rate the highest?

• A. From the 0ᵗʰ minute to the 2ⁿᵈ minute
• B. From the 2ⁿᵈ minute to the 4ᵗʰ minute
• C. From the 4ᵗʰ minute to the 6ᵗʰ minute
• D. From the 10ᵗʰ minute to the 12ᵗʰ minute

Consider the reaction between methyl methanote and dilute sodium hydroxide solution:

HCO₂CH₃(l) + NaOH(aq) → HCO₂Na(aq) + CH₃OH(aq)

Which of the graphs best represents the variation of [CH₃OH(aq)] with time from the start of the mixing of the two reactants?

• A
• B
• C
• D

Consider the following reaction:

5Br⁻(aq) + BrO₃⁻(aq) + 6H⁺(aq) → 3Br₂(aq) + 3H₂O(l)

Which of the following expressions for the rate of this reaction is correct?

• A. ∆[Br⁻(aq)]/∆t = 5 × ∆[H⁺(aq)]/∆t

• B. ∆[Br⁻(aq)]/∆t = 6/5 × (∆[H⁺(aq)]/∆t)

• C. ∆[Br⁻(aq)]/∆t = 5/6 × (∆[H⁺(aq)]/∆t)

• D. ∆[Br⁻(aq)]/∆t = 6 × ∆[H⁺(aq)]/∆t

Refer to the graph. What is the instantaneous rate of the reaction at the 600ᵗʰ second?

• A. −4.75 × 10⁻⁴ mol dm⁻³ s⁻¹
• B. 5.75 × 10⁻⁵ mol mol⁻³ s⁻¹
• C. 6.75 × 10⁻⁶ mol dm⁻³ s⁻¹
• D. −6.75 × 10⁻⁶ mol dm⁻³ s⁻¹

An experiment, using the set-up shown in the diagram, was carried out to study the rate of reaction between calcium carbonate chips and excess dilute hydrochloric acid. The mass of the conical flask and its contents was measured every 20 seconds using an electronic balance. Which of the graphs best represents the experimental results?

• A
• B
• C
• D

Consider the following reaction:

NaOH(aq) + HCl(aq) → NaCl(aq) + H₂O(l)

By monitoring the concentration change of which chemical species below can we follow the progress of this reaction?

• A. H⁺(aq)
• B. Cl⁻(aq)
• C. Na⁺(aq)
• D. H₂O(l)

Liquid X reacted with solid Y to form a gas as one of the products. Which of the set-ups, as depicted in the diagrams, are suitable for use to follow the progress of this reaction?

• A. I and III
• B. II and III
• C. I and IV
• D. II and IV