in a freezer, 150g of water at 0degrees celcius is placed in an ice cube tray. how much energy, in kilocalories, must be removed to form ice cubes at 0 degrees celsius
q = mass x heat fusion.
q = 150g x 79.8 cal/g = ? calories. Convert to kcal.
To calculate the amount of energy required to remove heat from water and convert it into ice cubes, you need to consider the following:
1. The heat energy required to raise the temperature of the water from 0°C to its freezing point.
2. The heat energy required to convert the water at its freezing point to ice, without a temperature change.
Let's break down the calculation step by step:
1. The heat energy required to raise the temperature of the water from 0°C to its freezing point:
The specific heat capacity of water is approximately 1 calorie/gram°C. Therefore, to raise the temperature of 150g of water from 0°C to its freezing point, you need:
Heat energy = mass × specific heat capacity × temperature change
= 150g × 1 calorie/gram°C × (0°C - 0°C) [no temperature change]
Since there is no temperature change, no heat energy is required.
2. The heat energy required to convert the water at its freezing point to ice, without a temperature change:
To convert water at its freezing point to ice, you need to remove its latent heat of fusion. The latent heat of fusion for water is approximately 79.7 calories/gram. Therefore, the amount of heat energy required to form ice cubes from 150g of water would be:
Heat energy = mass × latent heat of fusion
= 150g × 79.7 calories/gram
Now, to convert calories to kilocalories, divide the result by 1000:
Heat energy in kilocalories = (150g × 79.7 calories/gram) ÷ 1000
Performing the calculation:
Heat energy in kilocalories = (150g × 79.7 calories/gram) ÷ 1000
= 11.955 kilocalories
Therefore, approximately 11.955 kilocalories of energy must be removed to form ice cubes from 150g of water at 0°C.
To calculate the amount of energy required to form ice cubes, we need to consider the heat of fusion of water.
The heat of fusion of water is the amount of energy required to convert one gram of water from its solid state (ice) to its liquid state (water) at its melting point of 0 degrees Celsius. The heat of fusion of water is typically given as 334 kilocalories per gram.
Since we have 150 grams of water, the total energy required to form ice cubes can be calculated as follows:
Energy = mass of water (in grams) x heat of fusion of water
Energy = 150 grams x 334 kilocalories per gram
Energy = 50,100 kilocalories
Therefore, 50,100 kilocalories of energy must be removed to form ice cubes at 0 degrees Celsius.