P4 (s) + 10 Cl2 (g) �¨ 4 PCl5 (s) ƒ¢H = -435.2 kcal

Based on the reaction shown, which statement is true?
A) When 30.97 g P4 (s) react, 435.2 kcal are released.
B) When 1 mol P4 (s) reacts, 435.2 kcal are released.
C) When 123.88 g P4 (s) react, 435.2 kcal are consumed.
D) When 208.22 g PCl5 (s) are produced, 435.2 kcal are consumed.
E) When 1 mol PCl5 (s) is produced, 435.2 kcal are released

See the answer below.

To determine the correct statement, we need to calculate the energy released or consumed based on the given balanced chemical equation.

The stoichiometric coefficient in front of each substance in the balanced equation represents the ratio in which they react. From the equation:

1 mol P4 (s) + 10 mol Cl2 (g) → 4 mol PCl5 (s)

we can see that when 1 mol of P4 reacts, 4 mol of PCl5 is produced.

The heat change, ∆H, for the reaction is given as -435.2 kcal. This means that 435.2 kcal of energy is released during the reaction.

Now, let's use the molar masses of the substances to convert the given amounts to moles:

Molar mass of P4 = 4 * 31.0 g/mol = 124.0 g/mol
Molar mass of PCl5 = 1 * 31.0 g/mol + 5 * 35.5 g/mol = 208.5 g/mol

A) When 30.97 g P4 (s) react, we can calculate the number of moles:
30.97 g P4 * (1 mol P4 / 124.0 g P4) = 0.2499 mol P4
According to the balanced equation, this would produce:
0.2499 mol P4 * (4 mol PCl5 / 1 mol P4) = 0.9996 mol PCl5
This is not the correct statement since it does not match the given value of ∆H.

B) When 1 mol P4 (s) reacts, we already know that 435.2 kcal are released.
This matches the given value of ∆H, so this is the correct statement.

C) When 123.88 g P4 (s) react, we can calculate the number of moles:
123.88 g P4 * (1 mol P4 / 124.0 g P4) = 0.998 mol P4
According to the balanced equation, this would produce:
0.998 mol P4 * (4 mol PCl5 / 1 mol P4) = 3.992 mol PCl5
This is not the correct statement since it does not match the given value of ∆H.

D) When 208.22 g PCl5 (s) are produced, we can calculate the number of moles:
208.22 g PCl5 * (1 mol PCl5 / 208.5 g PCl5) = 0.9999 mol PCl5
According to the balanced equation, this would require:
0.9999 mol PCl5 * (1 mol P4 / 4 mol PCl5) = 0.2499 mol P4
This is not the correct statement since it does not match the given value of ∆H.

E) When 1 mol PCl5 (s) is produced, we already know that 435.2 kcal are released.
This matches the given value of ∆H, so this is also a correct statement.

Therefore, the correct statements are B) When 1 mol P4 (s) reacts, 435.2 kcal are released, and E) When 1 mol PCl5 (s) is produced, 435.2 kcal are released.