1. Quiz
A toy balloon has an internal pressure of 1.05 atm and a volume of 5.0 L. If the temperature where the balloon is released is C, what will happen to the volume when the balloon rises to an altitude where the pressure is 0.65 atm and the temperature is –15 0C?
What is the volume of 0.4 moles of O2 at STP?
A sample of gas is collected over water at a temperature of 35.0oC when the barometric pressure reading is mm Hg. What is the partial pressure of the dry gas? PH2O = 42.2 mm Hg)
If I have 12 moles of iodine gas (I2), what will the volume be if temperature is 310K and the pressure is 0.8 atm?

3. A gas at 273K at 800. torr is heated to 390K
A gas at 273K at 800. torr is heated to 390K. What is the new pressure of the gas?
A gas occupies 11.4 L at 25°C. What is the temperature in °C of the gas if the volume decreases to 5.6L?
2045 kPa is how many psi?
A gas occupies 11.4 L at a pressure of 36 mm Hg. What is the volume when the pressure is increased to 50 mm Hg?
State the Gay Lussacs’ law in words.

4. A gas at 273K at 800. torr is heated to 390K
A gas at 273K at 800. torr is heated to 390K. What is the new pressure of the gas?
A gas occupies 11.4 L at 25°C. What is the temperature in °C of the gas if the volume decreases to 5.6L?
2045 kPa is how many psi?
A gas occupies 11.4 L at a pressure of 36 mm Hg. What is the volume when the pressure is increased to 50 mm Hg?
State the Charles’ law in words.

5. 1142 torr
-127 °C
296.8 psi
8.2 L
GL law states Pressure and temperature are directly related

6. Lecture 6.2 Ideal Gas Law

7. We will use a simplified version, called the ideal gas law
Real gasses have many different forces acting on it making it very difficult to calculate variables accurately.
Particles itself has small volume
Particles have small attraction between each other
NASA would have to use complex equations to account for the minute volume of particles and attraction
We will use a simplified version, called the ideal gas law

8. Ideal gas law (basically the combined gas law, but it also accounts for # of moles)
PV=nRT
P=pressure in atm
V=volume in L
n= # of moles
R= a constant, equal to 𝑎𝑡𝑚·𝐿 𝑚𝑜𝑙·𝐾
T= temperature in Kelvin

9. P= V= n= T=

10. Using the ideal gas law, we can find P, V, n, or T.
If I have 3 moles of oxygen gas at 320 K in a 6L bottle, what is the pressure? P= V= n= R= T=

11. If I have a gas that is inside a 2. 5 L ballon, with a pressure of 2
If I have a gas that is inside a 2.5 L ballon, with a pressure of 2.75 atm, at a temperature 297 K, how many moles of the gas will be in the balloon? P= V= n= R= T=
=0.28 mol

12. Molar Volume
If I have a mole of any gas at 1 atm and 273K (0°C), it will always have a volume of 22.4 L
22.4 L or mole
1 mole L
1 atm and 273K condition is called the Standard Temperature and Pressure (STP)
Try solving using ideal gas law
V= nRT/P
1*R*273/1= 22.4

13. If I have 2 moles of oxygen gas (O2) at STP, what is the volume of the gas?
If I have 2 moles of helium gas (He)at STP, what is the volume of the gas?
If I have 4.32 moles of N2 at STP, what is the volume of the gas?

14. If I have 44.8 L of O2 at STP, what is the number of moles of the gas?
If I have 30.6 L of fluorine gas (F2) at STP, what is the number of moles of the gas?

15. Density of Gasses D=M/V The density of a gas at STP is= D= molar mass
molar volume

16. What is the density of He at STP?
The molar mass of He is 4.00g/mol
Molar volume of any gas at STP is 22.4 L
4.00g/mol = g/L
22.4L/mol

17. Practice What is the density of chlorine gas (Cl2) at STP?
What is the density of argon gas (Ar) at STP?

18. What is the molar mass of a gas that has a density of 1.836 g/L at STP?
1.836 g/L = X g/mol
22.4 L/mol
X= g/mol

19. Practice
What is the molar mass of a gas that has a density of 4.6 g/L at STP?
What is the molar mass of a gas that has a density of g/L at STP?

20. Partial Pressure
The total pressure of a mixture of gases equal to the sum of the partial pressure
Ptotal = P1 + P2   Pn

21. If carbon dioxide, nitrogen, and oxygen are in a container and exert a pressure of 760 torr, and the partial pressure of carbon dixoide is torr, the partial pressure of nitrogen is torr, what is the partial pressure of oxygen?
PTotal = PCO2 + PN2 + PO2
760= X
PO2 = 166 Torr

22. The atmosphere’s composition is 78% nitrogen, 21% oxygen, 1% argon
The atmosphere’s composition is 78% nitrogen, 21% oxygen, 1% argon. If the atmospheric pressure was 760 mm Hg, what pressure would be N? O? Ar?
760 * .78 = 590 mmHg N2
760 * .21 = 160 mmHg O2
760 * .01 = 8 mmHg Ar

24. Quiz 7.4 If I have 5 moles of N2 at STP, what is the volume?
If I have 35 L of O2 at STP, how many moles is it?
If I have a gas that is inside a 5.5 L balloon, with a pressure of 2 atm, at a temperature of 50⁰C, how many moles of the gas will be in the balloon?