37 . A flask contains three times as many moles of H 2 gas as it does O 2 gas. If hydrogen and
oxygen are the only gases present, what is the total pressure in the flask if the partial
pressure due to oxygen is P?
(A) 4 P
(B) 3 P
(C) 4/3P
(D) 3/4P
(E) 7 P38 . How many mL of a 0.25 N solution of HCl are needed to completely neutralize 5 grams of
crystalline NaOH dissolved in water?
(A) 150
(B) 250
(C) 500
(D) 750
(E) 3,75039 . Using the table below, what is the heat of combustion of one mole of C 2 H 4 at 298 K and 1
atm?
Compound ∆H of formation
(kcal/mol)
H 2 O (g) –57.8
C 2 H 6 (g) –20/2
C 2 H 4 (g) 12.5
C 2 H 2 (g) 54.2
CO (g) –26.4
CO 2 (g) –94.1