avogadro’s law ideal gases and molar volume. avogadro’s law 1 mol h 2 at stp = 22.4 l1 mol o 2...
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Avogadro’s lawIdeal gases and molar volume
Avogadro’s Law
1 mol H2 at STP = 22.4 L 1 mol O2 at STP = 22.4 L
STP stands for standard temperature & pressure
(0°C and 1 atm)
Avogadro’s Law
equal volumes of gases at the same temperature and pressure contain equal numbers of molecules.
Constant temperatureConstant pressure
Molar Volume of GasesThe volume occupied by one mole of a
gas at STP is known as the standard molar volume of a gas. It has been found to be 22.4 L.
1 mol = 22.4 L will be the conversion factor used in Avogadro’s law.
Sample Problem 1
A chemical reaction produces 0.0680 mol of oxygen gas. What volume in liters is occupied by this gas sample at STP?
Using our conversion factor of 1 mol = 22.4 L to solve for volume
1 mol
0.0680 mol x 22.4 L = 1.52 L O2
Sample Problem 2
A chemical reaction produced 0.098 L of sulfur dioxide gas, SO2, at STP. What was the mass (in grams) of the gas produced?
Sample Problem 2
First find molar mass of SO2:
1 x S = 32.07 g/mol
2 x O = 16 x 2 = 32 g/mol
64.07 g/mol
1 mol22.4 L
0.098 L SO2 x 1 mol x 64.07 g = 0.28 g SO2