Checkpoint #3

You should now be able to...

• Calculate the half-life of a reactant in a first-order reaction.

• Identify the difference between a differential and an integrated rate equation.

• Apply the integrated first order rate equation.

Practice Question 1

A reaction was found to be first order with a rate constant of 4.38 × 10^-4 s^-1.

How much of the starting material remains after 2675 seconds?

Practice Question 3

The rate equation for the reaction A + B → C reads:

Rate = k [A]² [B]

What is the overall order of this reaction?

Checkpoint #2

You should now be able to...

• Determine orders and rate constants from initial rate data.

Practice Question 1

The rate equation for the process

2NO(g) + O₂(g) ⟶ 2NO₂(g)

is found experimentally to be

rate = k [NO]² [O₂]

What are the orders with respect to each reactant and the overall order?

Try this yourself.

What are the orders with respect to each reactant and the overall order?

In part B of this experiment 2.0 g of NaOH (molar mass = 40.0 g/mol) is mixed with 100 mL of 1.0 M HCl. Which one of these statements is true?

Calculate the amount of heat required to raise the temperature of 633.3 mL of a solution from 21.6 °C to 35.3 °C if the solution has a density of 1.04 g mL^–1 and a heat capacity of 4.08 J K^–1 g^–1.

In this experiment you will draw graphs of temperature vs. time showing how the solution temperatures vary before and after mixing. An example is shown below.

From which point on this graph should the temperature of the mixture be recorded?

Practice Question 2

If the temperature of a reaction increases, the rate of the reaction increases. Why is this? (Select all that apply).

Checkpoint #1

You should now be able to...

• Define the rate for a given reaction in terms of the change of concentrations over time.

• Explain how changing temperature and concentration affects rates at a microscopic level.

Practice Question 1

Which one of the following is a valid expression for the rate of the reaction below?

4 NH₃  +  7 O₂    4 NO₂  +  6 H₂O

In this experiment you will draw graphs of temperature vs. time showing how the solution temperatures vary before and after mixing. An example is shown below.

From which point on this graph should the temperature of the mixture be recorded?