STP Gas Calculations

1
STP Gas Calculations

• One-step problems

A balloon is filled with 3.78 L of He gas at STP.
How many moles of helium atoms are inside?
He
Solution
1 mol
3.78 L He
0.169 mol He
22.4 L
2
STP Gas Calculations

• One-step problems

A balloon is filled with 5.99 moles of CH4 gas at
STP. What is the volume of the balloon in liters?
CH4
Solution
22.4 L
5.99 mol CH4
134 L CH4
1 mol
3
STP Gas Calculations

• One-step problems

A balloon is filled with 36.2 liters of Cl2 gas
at STP. How many moles of chlorine gas are
inside?
Cl2
Solution
1 mol
36.2 L Cl2
1.62 mol Cl2
22.4 L
4
STP Gas Calculations

• One-step problems

A balloon is filled with 0.333 mol of Xe gas at
STP. What is the liter volume of xenon in the
balloon?
Xe
Solution
22.4 L
0.333 mol Xe
7.46 L Xe
1 mol
5
STP Gas Calculations

• One-step problems

A balloon is filled with argon gas at STP. What
is the density of the gas in the balloon?
Ar
Solution
39.948 g Ar
1 mol
1.78 g/L Ar
22.4 L
1 mol
6
STP Gas Calculations

• One-step problems

A balloon is filled with an unidentified gas at
STP. If its density is 2.35 g/L, what is the
molar mass of this gas?
?
Solution
2.35 g gas
22.4 L
52.6 g/mol
1 mol
1 L
7
STP Gas Calculations

• One-step problems

A balloon is filled with acetylene gas at STP.
What is the density of the gas in the balloon?
C2H2
Solution
26.038 g C2H2
1 mol
1.16 g/L C2H2
22.4 L
1 mol
8
STP Gas Calculations

• One-step problems

A balloon is filled with a diatomic gas at STP.
If its density is 0.0900 g/L, what is the molar
mass of this gas?
?
What is the identity of this diatomic gas?
Solution
Hydrogen H2
0.0900 g gas
22.4 L
2.02 g/mol
1 mol
1 L
9
STP Gas Calculations

• Two-step problems

He
A balloon is filled with 300. liters of helium
gas at STP. What is the mass in grams of this
gas?
Solution
1 mol
4.0026 g He
300. L He
53.6 g He
22.4 L
1 mol
10
STP Gas Calculations

• Two-step problems

N2
A balloon is filled with 122 grams of nitrogen
gas at STP. What is the volume in liters of this
balloon?
Solution
1 mol
22.4 L
122 g N2
97.6 L N2
28.0134 g N2
1 mol
11
STP Gas Calculations

• Two-step problems

A balloon is filled with 487 liters of hydrogen
gas at STP. What is the mass in grams of this
gas?
H2
Solution
1 mol
2.01588 g H2
487 L H2
43.8 g H2
22.4 L
1 mol
12
STP Gas Calculations

• Two-step problems

A balloon is filled with 349 grams of neon gas at
STP. What is the volume in liters of this
balloon?
Ne
Solution
1 mol
22.4 L
349 g Ne
387 L Ne
20.1797 g Ne
1 mol
13
STP Gas Calculations

• Two-step problems

Several balloons are filled with 8250 total
liters of helium gas at STP. How many total
atoms of helium are contained in all of the
balloons?
Solution
1 mol
6.02x1023 atoms
8250 L He
2.22x1026 atoms
22.4 L
1 mol
14
STP Gas Calculations

• Two-step problems

A balloon in the shape of Darth Vaders head is
filled with 8.0x1028 molecules of nitrogen gas at
STP. What is the volume in liters of this
balloon?
Solution
1 mol
22.4 L
8.0x1028 molec.
3.0x106 L N2
6.02x1023 molec.
1 mol
15
STP Gas Calculations

• Two-step problems

A sleeping balloon is filled with 2.75 liters of
carbon dioxide gas at STP. How many molecules
are contained the balloon?
Solution
1 mol
6.02x1023 molecules
2.75 L CO2
7.39x1022 molecules
22.4 L
1 mol
16
STP Gas Calculations

• Two-step problems

A large yellow ducky balloon is filled with
2.5x106 liters of air at STP. What is the mass
in grams of the air if the average molar mass is
29 g/mol?
Solution
1 mol
29 g air
2.5x106 L air
3.24x106 g air
22.4 L
1 mol
17
STP Gas Calculations

• Two-step problems

The Goodyear Blimp is filled with 5.74x106 liters
of He at STP. What is the mass in grams of this
much He?
Solution
1 mol
4.0026 g He
5.74x106 L He
1.03x106 g He
22.4 L
1 mol
18
STP Gas Calculations

• Two-step problems

If the balloon at the left were filled with
4.5x1028 molecules of methane gas at STP instead
of air, what would be the volume in liters?
Solution
This sort of gives new meaning to the term
air head doesnt it?
1 mol
22.4 L
4.5x1028 molec.
1.7x106 L CH4
6.02x1023 molec.
1 mol
19
STP Gas Calculations

• One-step problems

If this flying cow balloon was filled with sulfur
dioxide gas at STP instead of hot air, what
would its density be?
Solution
64.064 g SO2
1 mol
2.86 g/L SO2
22.4 L
1 mol
20
STP Gas Calculations

• One-step problems

If these balloons are filled with gas at STP and
their density is 1.85 g/L, what is the molar mass
of this gas?
Solution
1.85 g gas
22.4 L
41.4 g/mol
1 mol
1 L
21
STP Gas Calculations

• Two-step problems

If this girl inhales all of the helium from this
balloon that has a volume of 1.25 liters at STP,
how many atoms does she inhale?
Solution
1 mol
6.02x1023 molecules
1.25 L CO2
3.36x1022 atoms of He
22.4 L
1 mol
22
STP Gas Calculations

• Two-step problems

If this girls balloon is filled with 4.0 liters
of CO2 gas at STP and someone popped it with a
pin, what mass in grams would be released?
Solution
1 mol
44.010 g CO2
4.0 L CO2
7.86 g CO2
22.4 L
1 mol