Question

find the mass of 44.8 liter of ammonia gas at stp ( n=14,h=1)
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Answer 1

Answer: use the ideal gas law -

PV = nRT

P is pressure (1 under STP), V is the volume in liters, n is the number of moles, R is the gas constant (0.082) and T the temperature in Kelvins (273 under STP). So, rearrange for n and solve and you get:

n=PV/RT = 1*44.8/(0.082*273) = 2 moles.

Ammonia is NH3 so the molecular weight is 17 g/mole. To get the mass, multiple the # moles times the molecular weight:

2 moles * 17 grams/mole = 34 grams