G10 Q2 Chem Review - Pt. 1 (B2027)

Which of the following changes would increase the rate of a reaction?

• Decreasing the temperature

• Adding a catalyst

• Adding more solvent into the reaction vessel

• Using blocks of solid reactants instead of powder

An irreversible reaction A + B → 2C is carried out under various conditions, but always with [B]₀ in excess. Plots of ln([A]) as a function of time for each reaction are linear, and the slopes of these plots do not depend on the initial concentration of B. What is the rate law for the reaction under these conditions?

• rate = k[A][B]

• rate = k[A][B]^-1

• rate = k[A]

• rate = k[A]²

The isotope cobalt-57 has a half-life of 272 days. How many days will it take a sample of ⁵⁷Co to decay to 76% of its original activity?

(Provide your answer to the nearest whole number)

Consider the reaction: SO₂Cl₂ --> SO₂ + Cl₂

What is the rate constant of the reaction?

• k = 4.296 x 10^-5

  M s^-1

• k = 2.198 x 10^-5

  s^-1

• k = 4.296 x 10^-5

  s^-1

• k = 2.198 x 10^-5

  M^-1 s^-1

• k = 4.296 x 10^-5

  M^-1 s^-1

Answer explanation

y = mx + b

y = ln(A)

x = t

m = -k = -2.198543

b = ln(A₀) = -2.30276

r^2 = 0.999

Consider the same previous reaction: SO₂Cl₂ --> SO₂ + Cl₂. An experiment was conducted wherein an initial concentration of 0.100 M of SO₂Cl₂ inside a 0.5 L container was reacted. What is the concentration of SO₂Cl₂ after 10 hours?

(k = 2.198 x 10^-5 s^-1)

(Report your answer to 3 s.f. and numerically only)

Consider the same previous reaction: SO₂Cl₂ --> SO₂ + Cl₂. An experiment was conducted wherein an initial concentration of 0.100 M of SO₂Cl₂ inside a 0.5 L container was reacted. How many moles of SO₂ is produced?

(k = 2.198 x 10^-5 s^-1)

(Report your answer to 1 s.f. and in decimal form only)

The figure shows experimental data of the time evolution of [C₄H₆] (denoted as [A]) in the dimerization reaction of butadiene. How many seconds will it take for only half of the initial amount of butadiene to be left inside the reaction vessel?

(Report your answer to 3 s.f. and numerically only)

Answer explanation

y = mx + b

y = 1/[A]

x = t

m = k = 0.110

b = 1/[A]₀ = 0.502

r² = 0.999

A mechanism for the reaction of nitric oxide and hydrogen to form water and nitrogen gas is proposed. What is the rate law predicted by this proposed mechanism?

• k[NO]²

• k[NO]²[H₂]

• k[NO]²[H₂]²

• k[NO]²[H₂]²[N₂O]^-1

  [H₂O]^-1

The following mechanism was proposed for the reaction between NO and Br to form NOBr.

What is the order of the reaction with respect to NO?

• 0

• 1

• 2

• 3/2

The graph shows the reaction profile of A+B-->C+D. What is the activation energy of the reaction C+D-->A+B ?

• 25 kJ

• 55 kJ

• 85 kJ

• -30 kJ