Which of the following phase transitions gives off more heat: (a) 1 mole of steam to 1 mole of water at 100ºC, or (b) 1 mole of water to 1 mole of ice at 0.0ºC?

How much energy is needed to turn 10.0 g of water at 25°C to steam ( = 6.01 kJ/mol;  = 40.76 kJ/mol; c = 75.3 J/mol • °C)?

Steam at 100oC was passed into a flask containing 276.87g of water at 21oC, where steam condensed. How many grams of steam must have condensed if the temperature of water in the flask was raised to76.1oC? The heat of vaporization of water (delta H) at 100oC is 40.7 kJ/mol and the specific heat is 4.18 J/g.oC.

Substance C has a normal boiling point of 89.3 ºC, and an enthalpy of vaporization of 31.3 kJ/mol.  How many kilojoules of heat is required to change 3.675 mol of C from a liquid at 89.3 ºC to a gas at 89.3 ºC?

How much heat must be added to 100 g of ice at -5°C to turn it into 60 grams of water and 40 grams of steam, both at 100°C? Cp H2O = 75.7 J/mol-K, Cp Ice = 37.7 J/mol-K, Cp Steam = 35.1 J/mol-K, ΔHfus = 6.01 kJ/mol, ΔHvap = 40.7 kJ/mol

What quanity of energy does it take to convert 0.451 kg ice at -20.0 degrees celcius to steam at 250.0 degrees celcius? Specific heat capacities: Ice, 2.03J/g degrees celcius; liquid, 4.18 J/g degrees celcius; steam, 2.02 J/g degrees celcius. delta H vap = 40.7kJ/mol; deltaHfus = 6.02kJ/mol

What amount of heat, in kJ, is required to convert 2.70 g of water at 67.0 °C to 2.70 g of steam at 100.0 °C? (specific heat capacity of water = 4.184 J/g • °C; ∆Hvap = 40.7 kJ/mol)