Use the following decay curve for iodine-131 to answer problems a to c: (5.4) a. Complete the values for the mass of radioactive iodine-131 on the vertical axis. b. Complete the number of days on the horizontal axis. c. What is the half-life, in days, of iodine-131

a. 80 g ⟶ 40 g ⟶ 20 g ⟶ 10 g ⟶ 5 g …

b. 0 da ⟶ 8 da ⟶ 16 da ⟶ 24 da ⟶ 32 da …

c. 8 da

Explanation:

Assume that the decay curve looks like the first one below.

a. Mass of I

The mass of iodine decreases by half after each half-life.

Thus, the masses decrease in the sequence

80 g ⟶ 40 g ⟶ 20 g ⟶ 10 g ⟶ 5 g …

b. Time

The horizontal axis has repeating units every 8 da.

Thus, the time increases in the sequence

0 da ⟶ 8 da ⟶ 16 da ⟶ 24 da ⟶ 32 da …

The completed graph is the second one below.

c. Half-life

It takes 8 da for 80 g of iodine to decrease to 40 g.

The half-life of iodine is 8 da.

did you find the answer?

if the concentration of products is decreased, the equilibrium will shift toward the products). add an inert gas (one that is not involved in the reaction) to the constant-volume reaction mixture: this will increase the total pressure of the system, but will have no effect on the equilibrium condition.

explanation: