Answer:
0.8749 grams of hydrogen gas was formed from the reaction.
Explanation:
P = Pressure of hydrogen gad= 744 Torr = 0.98 atm
(1 atm = 760 Torr)
V = Volume of hydrogen gas= 11 L
n = number of moles of hydrogen gas= ?
R = Gas constant = 0.0821 L.atm/mol.K
T = Temperature of vapor = 27.0 °C = 300.15 K
Putting values in above equation, we get:
Using an ideal gas equation:


n = 0.4374 moles
Mass of 0.4374 moles of hydrogen gas:
0.4374 mol × 2 g/mol = 0.8749 g
0.8749 grams of hydrogen gas was formed from the reaction.
When a water vapor condenses, heat is being released from the process. This heat is called latent heat of vaporization since the phase change happens without any change in the temperature. This value is constant per mole of a substance as a function of pressure and temperature. For this problem, we are given the heat of vaporization at a certain T and P. We use this value to calculate the total heat released from the process. We calculate as follows:
Total heat released: 32.4 g ( 1 mol / 18.02 g ) (40.67 kJ / mol) = 73.12 kJ
Therefore, 73.12 kJ of heat is released from the condensation of 32.4 g of water vapor.