Question

part a
find q for the evaporation of 385 g of water at this temperature.
express your answer to three significant figures and include the appropriate units.
q = 870 kj.

part b
find w for the evaporation of 385 g of water at this temperature. assume that the density of the compound in its liquid state is 1.00 g/ml.
express your answer to three significant figures and include the appropriate units.
w = - 66.2 kj

part c
find δu for the evaporation of 385 g of water at this temperature. assume that the density of the compound in its liquid state is 1.00 g/ml.
express your answer to three significant figures and include the appropriate units.
δu = 804 kj

part d
find δh for the evaporation of 385 g of water at this temperature.
express your answer to three significant figures and include the appropriate units.
δh - value units

Explanation:

Step1: Recall the relationship between $\Delta H$ and $\Delta U$

$\Delta H=\Delta U + P\Delta V$. For the evaporation of water at constant - pressure, we can also use the fact that for a phase - change at constant pressure $q_p=\Delta H$ and from part A, $q = q_p=870\ kJ$ (since the heat transfer at constant pressure for the evaporation process is given in part A).

Step2: Identify the answer

Since $q_p=\Delta H$ for a constant - pressure process, $\Delta H$ for the evaporation of water is equal to the heat transferred at constant pressure.

Answer:

$\Delta H = 870\ kJ$