Assuming that the specific heat of the solution is 4.18 KJ and that the calorime
ID: 612295 • Letter: A
Question
Assuming that the specific heat of the solution is 4.18 KJ and that the calorimeter itself absorbs a negligible amount of heat, calculate delta H in kilojoules for the reaction K2O+H2O->2KOH. When 1.045 g of K2O is added to 50.0 mL of water at 25.0 C in a calorimeter, the temperature of the water increases to 41.5 C.Explanation / Answer
CaO(s) + H2O (l) --> Ca(OH)2 (aq) First find grams of water. Density of water 1.00g/ml. So. 1.00g/ml = m/50.0ml that is 50.0grams water. I like this approach. 1.045g CaO (J/g) + 1.045( 4.18J/gC)(32.3-25.0) + 50.0g H2O( 4.18J/gC)(32.3-25.0) = 0 This = -1490.514 J/g We want KJ/mol So. -1490.514/50.0g H20 = -29.81 kj/mol This sounds right, as delta H will be negative. The system is giving heat to the surroundings.