Answer
During this process, 16.7 kJ of heat were released.
Work Step by Step
1. Identify the objective.
- Find the number of kilojoules that are necessary to freeze 50.0 g of water at 0$^{\circ}$.
2. Find the conversion factors.
- To convert the mass in g to joules in a freezing process, we can use the Heat of Fusion for water.
Page 76: $\frac{334 J}{1g}$ and $\frac{1g}{334 J}$
And: $1 kJ = 1000 J$
3. Using the conversion factor, calculate the necessary heat:
$50.0g \times \frac{334 J}{1g} \times \frac{1kJ}{1000J} = 16.7 kJ$
4. Adjust the number to the correct number of significant figures.
- The used number that has the fewest number of significant figures is "50.0", with 3. Therefore, the result of the multiplication must have 3 SFs.
16.7 kJ = 16.7 kJ
5. Indicate whether heat was absorbed or released.
- During the freezing process, heat is released.
You can check this information on page 76.