Chemistry 12 Reaction Kinetics Review

Chemistry 12: Reaction Kinetics Review
1.

Looking at the expressions for reaction rate, write expressions with which you could express rates for the following reactions. (Hint: look at what happens to reactants and products.) Recall that solid or liquids can lose or gain mass, gases can lose or gain volume and aqueous solutions can increase or decrease in concentration. ("a" is done as an example.)
a)

Mg(s) + 2HCl(aq)

H2(g) + MgCl2(aq)

reaction rate = mass of Mg consumed unit time

b)

c)

or

reaction rate = volume of H2 produced unit time

or

reaction rate = decrease in [HCl] unit time

or

reaction rate = increase in [MgCl2] unit time
AgNO3(aq) + NaCl(aq)

C(s) + O2(g)

1

NaNO3(aq) + AgCl(s)

CO2(g)

2.

For each of the following reactions find a quantity or property which could be monitored in order to measure the rate of reaction. ("a" is done as an example.)
a)

3H2(g) + N2(g)

2NH3(g)
Pressure will decrease as reaction proceeds because you are going from 4 moles of reactants to 2 moles of products. Assuming you have a constant volume, less moles exert less pressure.

b)

CaCO3(s)

CaO(s) +

CO2(g)

Two things could be monitored here. Look at the states of everything carefully.

c)

2NO2(g)

N2O4(g)

brown

colourless
Two things could be monitored here. One is obvious.

3.

A chemist wishes to determine the rate of reaction of beryllium with hydrochloric acid. The equation for the reaction is:
Be(s) + 2HCl(aq)

H2(g) + BeCl2(aq)

A piece of beryllium is dropped into 1.00 L of HCl(aq) and the following data were obtained: Time
Mass of Beryllium
0s
0.020 g
4s
0.018 g
8s
0.016 g
12 s
0.014 g
16 s
0.012 g
20 s
0.010 g
a) Calculate the Rate of Reaction in grams of Be consumed per second.

Answer___________________

2

b) Calculate the Rate of Reaction in moles of Be consumed per second.

Answer___________________
c) What will happen to the [HCl] as the reaction proceeds?_________________________