A silod block of ice isa ta -20°C and heat is added until it completely turns intl water vapor.
To calculate the amount of heat needed to convert ice at -20°C into water vapor, we need to consider the energy required for each phase change. Let's break down the process step by step:
1. Heat required to raise the temperature of ice from -20°C to 0°C:
The specific heat capacity of ice is 2.09 J/g°C. So, to heat each gram of ice from -20°C to 0°C, we need to multiply its mass by the temperature change and the specific heat capacity.
2. Heat required to melt the ice at 0°C:
The specific heat capacity of water is 4.18 J/g°C. So, to melt each gram of ice at 0°C, we need to multiply its mass by the specific heat capacity.
3. Heat required to raise the temperature of water from 0°C to 100°C:
The specific heat capacity of water is still 4.18 J/g°C. To heat each gram of water from 0°C to 100°C, we need to multiply its mass by the temperature change and the specific heat capacity.
4. Heat required for the phase change from water to steam (vaporization):
The heat of vaporization (enthalpy of vaporization) for water is 2260 J/g. To completely vaporize each gram of water, we multiply its mass by the heat of vaporization.
Please note that calculations involving mass depend on the specific mass of the ice block you are considering. For example, if the mass of the ice block is 1000 grams (1 kg), you would perform the above calculations using a mass of 1000 grams.
The total heat required will be the sum of the heat from each step outlined above. Take into account the mass of the ice block to get a more accurate result.
Note: The calculations assume there are no energy losses to the surroundings and that there are no other factors, such as pressure or impurities, affecting the phase changes.