AP Chemistry Unit 5 Progress Check

Which of the following best describes the elementary step(s) in the reaction mechanism represented in the diagram above?

• One step:2X(g)+Y(g)→X₂Y(g)

• Two steps:Step 1:X(g)+Y(g)→XY(g)

  Step 2:X(g)+XY(g)→X2Y(g)

• Two steps:Step 1:2X(g)→X₂(g)

  Step 2:X₂(g)+Y(g)→X₂Y(g)

• Two steps: Step 1:2X(g)→X₂(g)

  Step 2:X₂(g)+Y(g)→X₂Y(g)

The diagram above shows the progress of the chemical reaction for the synthesis of ammonia from its elements. The adsorption of the N₂ molecules on the surface of Ru weakens the triple bond between the two N atoms. Based on the diagram, what is the role of Ru in this process?

• Ru is a catalyst.

• Ru is a reactant.

• Ru is a product.

• Ru is an intermediate.

The proposed mechanism for a reaction involves the three elementary steps represented by the particle models shown above. On the basis of this information, which of the following models represents an intermediate in the overall reaction?

• 
• 
• 
• 

Tags

NGSS.HS-PS1-2

NGSS.HS-PS1-4

O₃(g)+O(g)→2O₂(g)

The decomposition of O₃ occurs according to the balanced equation above. In the presence of NO, the decomposition proceeds in two elementary steps, as represented by the following mechanism.

Step 1:O₃+NO→NO₂+O₂(slow)

Step 2:NO₂+O→NO+O₂(fast)

Based on the information, which of the following is the rate law?

• Rate=k[O₃][NO]

• Rate=k[NO₂][O₂]

• Rate=k[NO₂][O]

• Rate=k[NO][O]

Tags

NGSS.HS-PS1-5

Step 1:2NO₂(g)→NO₃(g)+NO(g)(slow)

Step 2:NO₃(g)+CO(g)→NO₂(g)+CO₂(g)(fast)

A proposed two-step mechanism for the chemical reaction NO₂(g)+CO(g)→NO(g)+CO₂(g) is shown above. Which of the following equations is a correct rate law that is consistent with the elementary steps in the mechanism?

• Rate=k[NO₂]

• Rate=k[NO₂]²

• Rate=k[NO₃][CO]

• Rate=k[NO₂][CO]

Tags

NGSS.HS-PS1-5

Step 1:H₂+IBr→HI+HBr(slow)

Step 2:HI+IBr→I₂+HBr(fast)

A proposed mechanism for the reaction H₂+2IBr→I₂+2HBr is shown above. Two experiments were performed at the same temperature but with different initial concentrations. Based on this information, which of the following statements is correct?

• The rate of the reaction will undergo a 4-fold increase in the experiment in which the initial concentrations of both HI and IBr were doubled.

• The rate of the reaction will undergo a 2-fold increase in the experiment in which the initial concentrations of both HI and IBr were doubled.

• The rate of the reaction will undergo a 4-fold increase in the experiment in which the initial concentrations of both H₂ and IBr were doubled.

• The rate of the reaction will undergo a 8-fold increase in the experiment in which the initial concentrations of both H₂ and IBr were doubled.

Tags

NGSS.HS-PS1-5

Step 1:2NO⇄(NO)₂(fast)

Step 2:(NO)₂+O₂⇄2NO₂(slow)

The elementary steps in a proposed mechanism for the reaction 2 NO(g)+O₂(g)→2NO₂(g) are represented by the equations above. Which of the following is the rate law for the overall reaction that is consistent with the proposed mechanism?

• rate=k[NO]²

• rate=k[NO][O₂]

• rate=k[NO]²[O₂]

• rate=k[(NO)₂][O₂]

Tags

NGSS.HS-PS1-5

H₂(g)+I₂(g)→2HI(g)

For the reaction between H₂ and I₂, shown above, the following two-step reaction mechanism is proposed.

Step 1:I₂⇄2I(fast equilibrium)

Step 2:H₂+2I→2HI(slow)

What is the rate law expression for this reaction if the second step is rate determining?

• Rate=k[I2]

• Rate=k[H₂][I]²

• Rate=k[H₂][I₂]

• Rate=k[I2][I]²

Tags

NGSS.HS-PS1-5

Step 1:2X(g)⇄X₂(g)(fast)

Step 2:X₂(g)+Y(g)→X₂Y(g)(slow)

The rate law for the hypothetical reaction 2X(g)+Y(g)→X₂Y(g) is consistent with the mechanism shown above. Which of the following mathematical equations provides a rate law that is consistent with this mechanism?

• rate=k[X]²

• rate=k[X₂][Y]

• rate=k[X]²[Y]

• rate=k[2X][Y]

Tags

NGSS.HS-PS1-5

Grinding a seltzer tablet into powder increases the rate of reaction due to...

• increased concentration of reactants
• increased surface area
• increased speed of particles.
• better orientation of reactants

Tags

NGSS.HS-PS1-5