Question

question 3 (1 point)
the molar heat of vaporization of water is 42 kj/mol. how much energy is released by the condensation of 3.0g of water?
7.0 kj
250 kj
0.88 kj
130 kj

Explanation:

Step1: Calculate moles of water

Molar mass of \(H_2O\) is \(18\space g/mol\). Moles \(n=\frac{mass}{molar\space mass}=\frac{3.0\space g}{18\space g/mol}=\frac{1}{6}\space mol\).

Step2: Relate condensation energy to vaporization

Condensation is reverse of vaporization, so energy released \(Q = n\times\) molar heat of vaporization. \(Q=\frac{1}{6}\space mol\times42\space kJ/mol = 7.0\space kJ\).

Answer:

7.0 kJ (corresponding to the option "7.0 kJ")