The normal melting point of copper is 1357 K and heat of fusion of Cu is 13.05 KJ.
How much heat, in kilojoules, is evolved when a 3.70 kg sample of of molten Cu freezes?
Your heat of fusion should have units of kJ/mole NOT just kJ. I had to look it up so see what it is.
So, you must determine how many moles of copper are in 3.70 kg. (3700 g)
You will need to remember or look up the atomic weight of copper to do that.
Then multiply that number of moles by 13.05 kJ/mole.
To find the heat evolved when a sample of molten Cu freezes, we can use the equation:
Heat evolved = mass × heat of fusion
Given:
Mass of Cu sample = 3.70 kg
Heat of fusion of Cu = 13.05 kJ
First, let's convert the mass of Cu sample into grams:
Mass of Cu sample = 3.70 kg × 1000 g/kg = 3700 g
Next, we can substitute the values into the equation:
Heat evolved = 3700 g × 13.05 kJ/g
Now, let's calculate the heat evolved:
Heat evolved = 3700 g × 13.05 kJ/g
Heat evolved = 48105 kJ
Therefore, when a 3.70 kg sample of molten Cu freezes, approximately 48105 kJ of heat is evolved.
To calculate the amount of heat evolved when a sample of molten Cu freezes, we need to multiply the mass of the sample by the heat of fusion of copper.
Given:
Mass of the sample (m) = 3.70 kg
Heat of fusion of copper (ΔH) = 13.05 kJ
The formula to calculate the heat evolved is:
Q = m * ΔH
Substituting the given values:
Q = 3.70 kg * 13.05 kJ
Calculating the product:
Q = 48.185 kJ
Therefore, when the 3.70 kg sample of molten Cu freezes, approximately 48.185 kJ of heat is evolved.