Question

How much energy does a freezer have to remove from 11 g of water at 20 degrees Celsius to make ice at -12 degrees Celsius?

Answer 1

To calculate the energy required to freeze water, you need to consider the specific heat capacity of water and the latent heat of fusion.

The specific heat capacity of water is approximately 4.18 Joules per gram per degree Celsius (J/g°C). This means it takes 4.18 Joules of energy to raise the temperature of 1 gram of water by 1 degree Celsius.

The latent heat of fusion for water is approximately 334 Joules per gram (J/g). This represents the amount of energy required to convert 1 gram of water at its freezing point into ice at the same temperature.

Now, let's calculate the energy required to freeze 11 grams of water from 20 degrees Celsius to -12 degrees Celsius:

1. Calculate the energy required to cool the water from 20°C to 0°C: Energy = mass × specific heat capacity × temperature change Energy = 11 g × 4.18 J/g°C × (0°C - 20°C) Energy = -917.6 J

2. Calculate the energy required to freeze the water at 0°C into ice at -12°C: Energy = mass × latent heat of fusion Energy = 11 g × 334 J/g Energy = 3674 J

3. Add the two energies together: Total energy = -917.6 J + 3674 J Total energy ≈ 2756.4 J

Therefore, approximately 2756.4 Joules of energy would be required to freeze 11 grams of water from 20 degrees Celsius to ice at -12 degrees Celsius.