1. He STP Gas Calculations 1 mol 3.78 L He = 0.169 mol He 22.4 L
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
= mol He
22.4 L

2. CH4 STP Gas Calculations 22.4 L 5.99 mol CH4 = 134 L CH4 1 mol
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. Cl2 STP Gas Calculations 1 mol 36.2 L Cl2 = 1.62 mol Cl2 22.4 L
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. Xe STP Gas Calculations 22.4 L 0.333 mol Xe = 7.46 L Xe 1 mol
One-step problems:
A balloon is filled with 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. Ar STP Gas Calculations 39.948 g Ar 1 mol = 1.78 g/L Ar 1 mol 22.4 L
One-step problems:
A balloon is filled with argon gas at STP. What is the density of the gas in the balloon? Ar
Solution:
g Ar
1 mol
= 1.78 g/L Ar
1 mol
22.4 L

6. ? STP Gas Calculations 2.35 g gas 22.4 L = 52.6 g/mol 1 L 1 mol
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 L
1 mol

7. C2H2 STP Gas Calculations 26.038 g C2H2 1 mol = 1.16 g/L C2H2 1 mol
One-step problems:
A balloon is filled with acetylene gas at STP. What is the density of the gas in the balloon?
C2H2
Solution:
g C2H2
1 mol
= 1.16 g/L C2H2
1 mol
22.4 L

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

9. He STP Gas Calculations Solution: Two-step problems:
A balloon is filled with 300. liters of helium gas at STP. What is the mass in grams of this gas?
Gas
Vol
mole
Mass
(g)
Solution:
1 mol
g He
300. L He
= 53.6 g He
22.4 L
1 mol

10. N2 STP Gas Calculations Solution: Two-step problems:
A balloon is filled with 122 grams of nitrogen gas at STP. What is the volume in liters of this balloon?
Mass
(g)
mole
Gas
Vol
Solution:
1 mol
22.4 L
122 g N2
= 97.6 L N2
g N2
1 mol

11. H2 STP Gas Calculations Solution: 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
Gas
Vol
mole
Mass
(g)
Solution:
1 mol
g H2
487 L H2
= 43.8 g H2
22.4 L
1 mol

12. Ne STP Gas Calculations Solution: 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
Mass
(g)
mole
Gas
Vol
Solution:
1 mol
22.4 L
349 g Ne
= 387 L Ne
g Ne
1 mol

13. STP Gas Calculations Solution: Two-step problems: 1 mol 8250 L He
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?
Gas
Vol
mole
Atoms
Solution:
1 mol
6.02x1023 atoms
8250 L He
= 2.22x1026
atoms
22.4 L
1 mol

14. STP Gas Calculations Solution: Two-step problems: 1 mol 22.4 L
A balloon in the shape of Darth Vader’s head is filled with 8.0x1028 molecules of nitrogen gas at STP. What is the volume in liters of this balloon?
Solution:
Molecules
mole
Gas
Vol
1 mol
22.4 L
8.0x1028 molec.
= 3.0x106 L N2
6.02x1023 molec.
1 mol

15. STP Gas Calculations Solution: Two-step problems: 1 mol 2.75 L CO2
A sleeping balloon is filled with 2.75 liters of carbon dioxide gas at STP. How many molecules are contained the balloon?
Gas
Vol
mole
Molecules
Solution:
1 mol
6.02x1023 molecules
2.75 L CO2
= 7.39x1022
molecules
22.4 L
1 mol

16. STP Gas Calculations Solution: 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?
Gas
Vol
mole
Mass
(g)
Solution:
1 mol
29 g air
2.5x106 L air
= 3.24x106 g air
22.4 L
1 mol

17. STP Gas Calculations Solution: 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?
Gas
Vol
mole
Mass
(g)
Solution:
1 mol
g He
5.74x106 L He
= 1.03x106 g He
22.4 L
1 mol

18. This sort of gives new meaning to the term “air head” doesn’t it?
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:
Molecules
mole
Gas
Vol
This sort of gives new meaning to the term “air head” doesn’t it?
1 mol
22.4 L
4.5x1028 molec.
= 1.7x106 L CH4
6.02x1023 molec.
1 mol

19. STP Gas Calculations 64.064 g SO2 1 mol = 2.86 g/L SO2 1 mol 22.4 L
One-step problems:
If this flying cow balloon was filled with sulfur dioxide gas at STP instead of hot air, what would it’s density be?
Solution:
g SO2
1 mol
= 2.86 g/L SO2
1 mol
22.4 L

20. STP Gas Calculations 1.85 g gas 22.4 L = 41.4 g/mol 1 L 1 mol
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 L
1 mol

21. STP Gas Calculations Solution: Two-step problems: 1 mol 1.25 L CO2
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?
Gas
Vol
mole
Molecules
Solution:
1 mol
6.02x1023 molecules
1.25 L CO2
= 3.36x1022
atoms of He
22.4 L
1 mol

22. STP Gas Calculations Solution: Two-step problems:
If this girl’s 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?
Gas
Vol
mole
Mass
(g)
Solution:
1 mol
g CO2
4.0 L CO2
= 7.86 g CO2
22.4 L
1 mol