How much heat is necessary to change 20 g of ice at 0 degrees C into water at 0 degrees C?
20 grams times the latent heat of fusion, which is 80 calories per gram for water.
To calculate the amount of heat required to change a substance from one state to another, we need to use the equation:
Q = m * c * ΔT
where:
Q = heat energy (in joules)
m = mass of the substance (in grams)
c = specific heat capacity of the substance (in J/g°C)
ΔT = change in temperature (in °C)
In this case, we want to calculate the heat energy required to change 20 g of ice at 0°C into water at 0°C.
1. Determining the change in temperature (ΔT):
Since we are going from ice at 0°C to water at 0°C, the temperature change is 0°C - 0°C = 0°C.
2. Finding the specific heat capacity (c):
The specific heat capacity for ice is 2.09 J/g°C. This means that it takes 2.09 joules of heat energy to raise the temperature of 1 gram of ice by 1°C.
3. Calculating the heat energy (Q):
Using the formula Q = m * c * ΔT, we can substitute the values:
Q = 20 g * 2.09 J/g°C * 0°C
Q = 0 joules
Therefore, no heat energy is required to change 20 g of ice at 0°C into water at 0°C because they are already at the same temperature.