Converting liquid water to solid ice releases 1.44 kcal/mol (6.02 kJ/mol). How many kilocalories are released by freezing 32 g of H2O?

Verified step by step guidance

1. Determine the molar mass of H2O. The molar mass of H2O is calculated by adding the atomic masses of 2 hydrogen atoms and 1 oxygen atom.
2. Calculate the number of moles of H2O in 32 g. Use the formula: \( \text{moles} = \frac{\text{mass (g)}}{\text{molar mass (g/mol)}} \).
3. Use the given energy release per mole to find the total energy released. Multiply the number of moles by the energy released per mole (1.44 kcal/mol).
4. Ensure the units are consistent and the final answer is in kilocalories.
5. Review the calculation to ensure all steps are correctly followed and the units are properly converted if necessary.

Key Concepts

Molar Mass of Water

The molar mass of water (H2O) is approximately 18 g/mol. This value is essential for converting grams of water to moles, which is necessary for calculating the energy released during the phase change from liquid to solid.

Phase Change and Latent Heat

Phase change refers to the transition of a substance from one state of matter to another, such as from liquid to solid. The latent heat of fusion for water is the amount of energy released when water freezes, quantified as 1.44 kcal/mol, which is crucial for determining the total energy released when a specific mass of water freezes.

Energy Calculation

To find the total energy released during the freezing of water, one must calculate the number of moles in the given mass and then multiply by the latent heat of fusion. This involves using the formula: Energy = moles × latent heat, which provides the total energy in kilocalories for the specified mass of water.