# chemistry

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How much heat, in kilojoules, is evolved when a 3.70 kg sample of molten Cu freezes?
The normal boiling point is 1357 K, and heat of fusion is 13.05 KJ/mol.

2.) How much heat must be absorbed at 1357 K to melt a bar of copper (80 * 10 * 12 cm) assume d = 8.93 g/cm^3.

• chemistry -

What's the temperature of the molten Cu? I assume it's at the melting point and not above it.
Convert 3.70 kg to moles Cu.
moles Cu x heat fusion = ?? kJ.

• chemistry -

2.5*10^4

• chemistry -

3.78kg Cu x (1000g/1kg) x (1 mol/63.546g) = 59.5
mol Cu
59.5 mol Cu x (13.05kJ/1mol) = 776 kJ evolved

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