Question

When solving these could you please do it in steps so I can understand and repeat it with different numbers!

How many moles of an ideal gas must be present in a sample that is known
to have a pressure of 18 atm, a volume of 2 liters, and a temperature of 41°C?
a. 1.4 moles
b. 3.91 moles
c. 0.419 moles
d. 3.21 moles

If the gas is oxygen, what is the mass of this sample?
How many molecules are there in this sample?

What will the volume of 1 moles of ideal gas sample be at STP?

Answer 1

We know from ideal gas law

P, V denotes pressure and volume at temperature T and n denotes the number of moles.

R=0.08205 L atmp/mole K is the universal gas constant.

Given P=18 atmp

V=2 L

T=41℃=(41+273) K=314 K

Hence, option a is correct.

1 mole of Oxygen weighs 16 gm

Hence. 1.4 moles of oxygen will weigh

This is the atomic mass.

Molecular mass of 1.4 moles of oxygen is

1 mole of a gas contains Avogadro number of molecules.

At STP,

T=273 K

P=1 atmp

Considering 1 mole of ideal gas , applying ideal gas law

This is the volume of 1 mole of ideal gas at STP