The answer that he gave was wrong
1 answer:
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Answer:
Explanation:
Hello,
In this case, for latent heat (phase change) we need to consider the enthalpy associated with the involved process, here, melting or fusion; thus, the enthalpy of fusion of copper is 13.2 kJ/mol, therefore, the heat is computed as:
Nevertheless, since the given enthalpy is per mole of copper, we need to use its atomic mass to perform the correct calculation as follows:
Which is positive as it needs to be supplied to the system.
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Answer:
The heat needed to boil 1 gallon of water is 81,490.62 Joules.
Explanation:
Where:
Q = heat absorbed or heat lost
c = specific heat of substance
m = Mass of the substance
ΔT = change in temperature of the substance
We have :
Volume of water = V = 1 gal = 4546.09 mL
Density of water , d= 1 g/mL
mass of water = m = d × V = 1g/mL × 4546.09 mL = 4546.09 g
Specific heat of water = c = 1 Cal/g°C
ΔT = 100°C - 25°C = 75 °C
9 (boiling pint of water is 100°C)
Heat absorbed by the water to make it boil:
1 calorie = 4.184 J
The heat needed to boil 1 gallon of water is 81,490.62 Joules.