Suppose that the amount of heat removed when 42.1 kg of water freezes at 0.0 °C were removed from ethyl alcohol at its freezing/melting point of −114.4 °C. How many kilograms of ethyl alcohol would freeze?

Answer 1

heat removed when freezing 42.1 kg H2O = ?
mass H2O x heat fusion = ? joules
42,100 g x heat fusion = ? joules.
Then mass alcohol x heat fusion = joules.
You know heat fusion alcohol (you have that in the problem or you can look it up) and you have joules, solve for mass alcohol.