Question

For each of the following pairs of molecules, identify, which molecule holds the larger entropy value, and briefly (1-3 sentences) explain why.

a. 1 mol of H₂ O (l) or 1 mol of H₂O (g) (both at 100 C)

b. 1 mol of I₂ (g) or 1 mol of F₂ (g)

c. 3 mol of O₂ (g) or 2 mol of O₂ (g)

d. 1 cup of coffee at 35 C or 1 cup of coffee at 20 C

Answer 1

a. 1 mol of H2 O (l) or 1 mol of H2O (g)

Answer is 1 mol of H2O (g). Because gases are possess more entropy than liquid. Because the molecules are distributed throughout a much larger volume in the gaseous state than in the liquid state, an increase in motional freedom accompanies vaporization

1 mol of I2 (g) or 1 mol of F2 (g)

Answer is 1 mol of F2 (g). Because Iodine is larger molecule which are restricted to move in the particular volume. But in the same volume F2 will move faster and increasing entropy

c. 3 mol of O2 (g) or 2 mol of O2 (g)

Answer is 3 mol of O2 (g). If mole is high, then number of molecules and volume also high which have more available motions than solids.

d. 1 cup of coffee at 35 C or 1 cup of coffee at 20 C.

Answer is 1 cup of coffee at 35 C. Increasing temperatur will increase the entropy