Question

At 89.85 degree Celsius, a 100.0-ml sample of ammonia gas exerts a pressure of 6.90 atm. Assume ideal gas behavior, and calculate the mass of ammonia (NH3) in the sample.

Answer 1

Ideal gas equation is expressed as

PV = nRT

P = pressure = 6.90 atm

V = volume = 100 mL = 0.1 L

R = gas constant = 0.082057 L atm mol^-1 K^-1

T = 89.85 ^oC = (89.85 + 273) K = 362.85 K

n = number of moles = ?

Now, substituting the values in the ideal gas equation, we get;

PV = nRT

n = PV / RT

= [ (6.90 atm) (0.1 L) ] / [ (0.082057 L atm mol^-1 K^-1) (362.85 K) ]

= 0.0232 mol

Now,

Molar mass of NH3 = 17 g/mol

So, 1 mole of NH3 = 17 g

0.0232 mole of NH3 = 0.0232 x 17 g

= 0.3944 g