Calculate the energy pulled from 500 grams of Water at 20.0 degrees Celsius to Ice at 0.0 degrees Celsius.
What happens to the energy?
How much Freon-11 must circulate through the freezer in order to freeze the 500 gram sample of Water?
q1 = heat to move water from 20C to zero C.
q1 = mass H2O x specific heat water x (Tfinal-Tinitial).
q2 = heat to freeze 20 g H2O at zero C to ice at zero C.
q2 = mass water x heat fusion.
qtotal = q1 + q2.
qtotal = mass freon x heat vaporization if we assume 100% efficiency.
To calculate the energy needed to change the state of water from liquid to solid (ice), you need to know the specific heat capacity and the latent heat of fusion of water.
1. Calculate the energy required to cool the water from 20.0 degrees Celsius to 0.0 degrees Celsius:
- The specific heat capacity of water is 4.186 Joules per gram per degree Celsius (J/(g·°C)).
- The temperature change is 20.0 - 0.0 = 20.0 degrees Celsius.
- The mass of water is 500 grams.
- Multiply the mass by the specific heat capacity and the temperature change to get the energy:
Energy = mass * specific heat capacity * temperature change
Energy = 500 g * 4.186 J/(g·°C) * 20.0 °C
Energy = 41,860 Joules
2. Calculate the energy required to change the water from liquid to solid (latent heat of fusion):
- The latent heat of fusion of water is 334 J/g.
- The mass of water is 500 grams.
- Multiply the mass by the latent heat of fusion to get the energy:
Energy = mass * latent heat of fusion
Energy = 500 g * 334 J/g
Energy = 167,000 Joules
Now add the two energies together to get the total energy required:
Total Energy = Energy to cool + Energy for fusion
Total Energy = 41,860 Joules + 167,000 Joules
Total Energy = 208,860 Joules
What happens to the energy?
The energy is absorbed by the water to undergo a phase change from liquid to solid. This energy is used to break the intermolecular forces and arrange the water molecules into a crystalline structure.
As for the amount of Freon-11 required to freeze the water, it depends on the specific properties of the freezer, such as its efficiency and cooling capacity. The calculation would involve determining the necessary heat transfer rate and then finding the appropriate flow rate of Freon-11 through the system. This calculation requires detailed knowledge of the freezer's specifications and would generally be performed by refrigeration engineers or professionals.