c. A 2 kg block of ice has been stored in a chiller at a constant 0°C. In order to carry out an investigation, the block of ice needs to be turned into water at a temperature of 75°C.
Calculate how much heat energy is required to change the block of ice into water at 75°C. Assume the specific heat capacity of water is 4200 KJ/kg°C and the specific latent heat of fusion of water is 334 KJ/kg°C.
The total heat energy is the heat energy required to change ice to water, plus the energy to bring water from 0C to 75C.
a) Specific latent heat of fusion of water (per kg) = 334kJ
Heat required for two kgs = 334 x 2 = 668kJ
b) Heat for temp. change = C x M x (Difference in temperature)
= 4200kJ x 2 x 75
Add parts (a) and (b), and you'll get your answer
the 4200 should be Joules, NOT kJ
I agree with Scott, the specific heat of water is 4.18Kj/Kg (or aboaut 4.2kg/kg
so that heat would be 4.2kg/kg*2kg*75, that then is added to the heat of fusion (melting).
To calculate the heat energy required to change the block of ice into water at 75°C, we need to consider two processes: melting the ice and then heating the resulting water to 75°C.
1. First, we need to calculate the heat energy required to melt the ice. This can be done using the specific latent heat of fusion of water, which is 334 KJ/kg.
The formula to calculate the heat energy required for melting is:
Q = m * L_f
where Q is the heat energy, m is the mass of the ice, and L_f is the specific latent heat of fusion.
Given that the mass of the ice is 2 kg, we can substitute these values into the formula:
Q = 2 kg * 334 KJ/kg = 668 KJ
Therefore, the heat energy required to melt the ice is 668 KJ.
2. Next, we need to calculate the heat energy required to raise the temperature of the melted water from 0°C to 75°C. To do this, we can use the specific heat capacity of water, which is 4200 KJ/kg°C.
The formula to calculate the heat energy required for heating is:
Q = m * c * ΔT
where Q is the heat energy, m is the mass of the water, c is the specific heat capacity, and ΔT is the change in temperature.
In this case, since there is no change in mass (since the ice has been converted into water), we don't need to multiply by the mass. So the formula simplifies to:
Q = c * ΔT
Given that the specific heat capacity of water is 4200 KJ/kg°C and the change in temperature is from 0°C to 75°C, we can substitute these values into the formula:
Q = 4200 KJ/kg°C * 75°C = 315,000 KJ
Therefore, the heat energy required to heat the water from 0°C to 75°C is 315,000 KJ.
Finally, to get the total heat energy required, we add the heat energy for melting (668 KJ) to the heat energy for heating (315,000 KJ):
Total heat energy = 668 KJ + 315,000 KJ = 315,668 KJ
Therefore, the total heat energy required to change the block of ice into water at 75°C is 315,668 KJ.