Question

A 1.70 g sample of a certain metal reacts with acid to liberate 380 mL of hydrogen gas, when collected over water at 20 Celsius and over 720 torr. What is the equivalent mass of the metal?

Answer 1

M + 2HX ==> MX + H2
mols H2 = n
P = (720-vapor pressure H2O @ 20C)/760 atm
T = 273+ 20
V = 0.380 L
R = 0.08206 L*atm/mol*K
Solve for n.
Then mol = grams/molar mass and solve for molar mass.
Equivalent mass = molar mass/valence.

Answer 2

78-0