A sample of K(s) of mass 2.880g undergoes combustion in a constant volume calori
ID: 861013 • Letter: A
Question
A sample of K(s) of mass 2.880g undergoes combustion in a constant volume calorimeter at 298.15 K. The calorimeter constant is 1849 JK?1, and the measured temperature rise in the inner water bath containing 1524g of water is 1.60 K.
Chemistry!
A sample of K(s) of mass 2.880g undergoes combustion in a constant volume calorimeter at 298.15 K. The calorimeter constant is 1849 JK?1, and the measured temperature rise in the inner water bath containing 1524g of water is 1.60 K. Calculate delta Uf degree for K2O. Express your answer to three significant figures and include the appropriate units. Calculate delta Hf degree for K2O. Express your answer to three significant figures and include the appropriate units.Explanation / Answer
Heat absorbed by constant volume calorimeter = dq = capacity*dT= -1849*1.46 = -2.7*10^3j
Molecular weight K=39.1
Moles of K(s) burned = 2.88/39.1=
0.074
For constant volume dU=dq, dH=dU
dU for combustion of 1 mole of K =-2.7*10^3/0.074 = -36.5 Kj/mole
dH=dU=-36.5kj/mole