1. Ideal Gas Law
PV=nRT

2. Remember… Boyle’s Law Charles’ Law:
Combined Gas Law: (Units MUST Match Temp in Kelvin!!!)

3. A gas with a volume of 350 ml is collected at 15o C and 120 kPa
A gas with a volume of 350 ml is collected at 15o C and 120 kPa. If the temperature changes to 30o C, what pressure would be required to put this gas in a 300 ml container?

4. A balloon has a volume of 500 ml at a temperature of 22oC and a pressure of 755 mmHg. If the balloon is cooled to 0o C and a pressure of 145 mmHg, what is its new volume?

5. Avogadro’s Principle
Under similar conditions (same Temp and Pressure) equal volumes of gases contain equal numbers of particles.
10 L of H2 (g) and 10 L of O2 (g) Both at Standard Temperature and Pressure (STP) contain…
The same number of particles!

6. The volume of 1 mole of gas particles
Molar Volume
The volume of 1 mole of gas particles
at STP
is 22.4 L

7. Ideal Gas Law Animation:

8. Try this: 1 mole of gas occupies 22.4 L at STP = __________ ml (22400)
= ___________ moles of gas
(1 mole)
= ___________ particles
(6.02 x 1023)

9. How many particles in 11.2 dm3 of gas at STP?
0.5 moles = 3.01 x 1023 particles
22,400 cm3 of NH3 gas at STP weighs?
= 22.4 L = 1 mole = 17 grams (add up MW)
44.8 L of NH3 at STP weighs?
= 2 moles = 34 grams
_____ grams = 1 mole of nitrogen gas = _____ L at STP?
28.00
22.4

10. How many N2 molecules are in 22.4 dm3 at STP?
= 1 mole = 6.02 x 1023
What volume will 1.2 x 1024 H2 molecules occupy at STP?
= 2 moles = 44.8 L at STP

11. Ideal Gas Equation Use when NOT at STP!!!
PV= nRT
P = Pressure (in kPa)
V = Volume (in Liters or dm3)
n = number of moles
T = Temperature (in Kelvin)
R = L• kPa
mole • K

12. Development of R in

13. 1. What volume will 2 moles of NO2 occupy at 300 Kelvin and 90 kPa?

14. What will be the temp of 2 grams of H2 if 5000 cm3 is at 5 atm?

15. Finding Molecular Weight of a Gas
Remember: MW = grams / moles
Converting grams to moles
Divide grams by the molecular weight

16. PV=nRT 92kPa • 5.0 L= n • 8.31 • 293 K n = 0.19 mol
1) 5.0 L of a gas weighs g at 20o C & 92 kPa. What is the mole weight of the gas?
PV=nRT
92kPa • 5.0 L= n • 8.31 • 293 K
n = 0.19 mol

17. 2)If the mole weight of a gas is 26 g/mol and 18
2)If the mole weight of a gas is 26 g/mol and g of the gas is 30 L at 21o C, what is the pressure of the gas?
PV= nRT
P x 30 L=0.69 mol x 8.31 x 294 K
P = 56.2kPa

18. Stoichiometry Solving Steps. Balance the Equation
Change grams to moles
Use mole ratio to solve
Change moles to volumes

19. Use mole ratio (coefficients) Use MW on P.T. Use 22.4 L/mol
@ STP
Or PV = nRT
Use 22.4 L/mol
@ STP
Or PV = nRT
Use MW
on P.T.

20. Mg (c) + HCl (ag)  MgCl2 + H2 (g)
If 2.43 g Mg react what volume of H2 is produced? (at STP)
1:1
0.1 mole
0.1 moles
Mg (c) HCl (ag)  MgCl2 + H2 (g) 2
? L
2.24 L H2
2.43 g Mg

21. Mg (c) +2 HCl (ag)  MgCl2 + H2 (g)
If 2.43 g Mg react what volume of H2 is produced at 40oC and 85 kPa?
1:1
0.1 mole
0.1 moles
Mg (c) HCl (ag)  MgCl2 + H2 (g) 2
? L
3.06 L H2
2.43 g Mg

22. Mg (c) + HCl (ag)  MgCl2 + H2 (g)
If 250 ml of H2 is produced at 20o C & 100 kPa, what mass of Mg reacted?
1:1
0.01 mole
0.01 moles
Mg (c) HCl (ag)  MgCl2 + H2 (g) 2
0.243 g Mg
? g
250 ml

23. Volume to Volume THE MOLE RATIO IS THE SAME AS THE VOLUME RATIO.
Liters B
Use mole ratio
(coefficients)
Liters A

24. What vol. of oxygen is needed to completely burn 1 L of methane?
Burning of methane:
What vol. of oxygen is needed to completely burn 1 L of methane?
1:2
1.0 L
2.0 L
CH O2  CO2 (g) H2O (l) 2 2

25. To produce 11.2 L of CO2 requires how many moles of O2 at STP?
Burning of methane:
To produce 11.2 L of CO2 requires how many moles of O2 at STP?
2:1
1 mole =
22.4 L
11.2 L
CH O2  CO2 (g) H2O (l) 2 2