Chemistry - Standard temperature and pressure exercises

Volume = 5.5 X 22.4 = 0.25L

mole = V/22.4 = 1.12/22.4 =0.05
mass = mole X molar mass = 0.05 X 32 =1.6 grams

mole = V / 22/4 = 6.8 / 22.4 = 0.30 mole

Step 1 calculate the mole of gas
=> mole = V / 22.4 = 1.75 / 22.4 = 0.078
Step 2 calculate the molar mass
M =m / mole = 2.5 / 0.078 =32 grams/mole. This is close to the molar mass of oxygen

Standard temperature and pressure.
exercises

1) What is the volume occupied by 5.5 mole of nitrogren gas as S.T.P?
Answer
2) What mass of oxygen gas(O₂) occupies a volume of 1.12L at 0^oC and 760mmHg pressure. (Atomic mass O=16)
Answer
3) How many mole of helium gas should be placed in a piston so that is expands to fill a volume of 6.8L at S.T.P.?
Answer
4) 2.5 grams of an unknown gas occupies a volume of 1.75 litres at S.T.P. Scientists suspect nitrogen(N₂), oxygen(O₂), chlorine(Cl₂) or hydrogen(H₂) gas. Which one is it likely to be?
Atomic mass H=1,O=16,Cl=35.5,N=14.
Answer

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