Transcript Avogadro`s Law Gas Density

Avogadro’s Law
Gas Density
Relationships between amounts of gas and volume

The volume of a gas at constant
temperature and pressure is proportional
to the number of moles of gas:
◦Vn
  means “proportional to”
◦ V = kn
◦ V1/n1 = V2/n2
Avogadro’s Law

The volume of 1.0 mole of any gas at STP
is 22.4 L.
◦ This is called the standard molar volume.
The volume of any gas at STP can be
calculated if the number of moles is
known:
 V = (moles) x 22.4

Standard Molar Volume
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One mole of gas at STP has a volume of 22.4 L.
How many moles of gas are present in a 3.00 L
container at STP?
If 0.222 mol of a gas has a volume of 5.13 L. How
many moles of gas would be present if the volume
was 7.47 L (at the same temperature and
pressure)?
A 21.0 g lump of dry ice (carbon dioxide)
completely sublimes. The resulting CO2 gas
occupies a volume of 11.5 L. What would be the
volume of 1.00 mol of CO2?
22.0 g of CO2 occupies a volume of 11.2 L at STP.
Calculate the volume of 44.0 g of CO2 at STP.
Avogadro’s Law Problems
Density = mass/volume
 Calculate the density of CH4 at STP
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Assume 1 mole of CH4
V= 22.4 L
density = mass/volume = 16/22.4
0.714 g/L
Density of Gases
Calculate the density of chlorine gas at
STP.
2. Determine the density of helium gas at
STP.
3. What is the volume of 0.200 g of
hydrogen gas at STP?
4. How many moles of nitrogen gas can be
in a balloon with a volume of 6.00 L at
STP?
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Density of Gases Problems