1. Properties of all gases Chapter 14 with Ch 13 review. WOD are underlined.

2. Properties of all gases When working with gases, there are 4 properties that must be considered: Gas Properties: Mass, Volume, Pressure, Temperature There are multiple equations: The properties that change determine the equation to select to solve for the unknown. All the remaining properties must be held constant.

3. From Chapter 13 Phases Two of the properties determine the phase of an element: Pressure Temperature

4. From Chapter 13 Phases What happens when you increase pressure (a lot) on gas? (What is one exception?) What happens when you increase temperature (a lot) on a solid?

6. There is a pan of ice on the stove. What does this Temperature graph look like?

7. WRONG!

9. Properties of all gases KNOW ALL THE FOLLOWING: Pressure at STP is: –1 atm = 760 mm Hg = 101.3 kPa = 14.7 lbs/in 2 Volume –1 mL = 0.001L = 1cm 3 Temperature at STP is 273 K (0° Celsius) –Use Kelvin (not Celsius)

10. Standard Temperature and Pressure: STP, Temperature and Pressure at Sea Level on a freezing day = 101.3 kPa, 273 K KNOW ALL THE FOLLOWING: Pressure at STP is: –1 atm = 760 mm Hg = 101.3 kPa = 14.7 lbs/in 2 Volume –1 mL = 0.001L = 1cm 3 Temperature at STP is 273 K (0° Celsius) –Use Kelvin (not Celsius)

11. Properties of all gases Pressure –1 atm = 760 mm Hg = 101.3 kPa = 14.7 lbs/in 2 Discuss Gage pressure in a factory (diff from atm. Vs gage pressure in a lab (Boyles Law)

12. Boyle’s Law – what happens to pressure?

13. Boyle’s Law P 1 V 1 = P 2 V 2 (mass and temperature constant) Volume of a gas varies inversely with pressure V↑P↓ or P↑V↓ P 1 V 1 = P 2 V 2 Or PV = Constant

14. Steps to Solve Problems: 1. Known: Find the knowns. 2. Unknown: Find the unknowns. 3. Equation: Pick the equation that matches the knowns and unknowns. 4. Units: Make sure units are the same on both sides. T in Kelvin. 5. SigFig: Change the answer to the correct number of significant figures.

15. A 220mL balloon of air is at a pressure of 506.5kPa. What will be the volume of the balloon at sea level (STP)?

16. A 455mL balloon is taken from sea level up to a point where the pressure is unknown. The balloon has a new volume of 1.25L. What is the pressure?

17. Review the last 2 slides. As height goes up: What happens to pressure? What happens to volume?

18. NaHCO 3 + HC 2 H 3 O 2  H 2 O +NaC 2 H 3 O 2 + CO 2 At STP, 2.5g of NaHCO 3 produced 560 mL of CO 2 gas. What would the volume of this gas be on top of mountain where the pressure is only 250 mm Hg? Extra credit – What is the percent yield of CO 2 produced? (Use Mass ratio’s)

19. NaHCO 3 + HC 2 H 3 O 2  H 2 O +NaC 2 H 3 O 2 + CO 2 At STP, 2.5g of NaHCO 3 yields 560 mL of CO 2 P 2 = 250 mm Hg? Extra credit – What is the percent yield of CO 2 produced?

20. Charles’s Law – What happens to a gas if it is heated?

21. Charles’s Law V 1 /T 1 =V 2 /T 2 (mass and pressure constant) Volume of a gas varies directly with its Kelvin temperature T↑ V↑ or T↓V↓ V 1 /T 1 =V 2 /T 2 or V/T = Constant

22. A balloon is filled with 5.00L of air with a temperature of 0 0 C. The balloon is placed by a furnace and expands to 7.00L. What is the temperature next to the furnace? Hint: Use 273K

23. Gay-Lussac’s Law P 1 /T 1 =P 2 /T 2 (mass and volume constant) pressure of a gas varies directly with its Kelvin temperature P↑ T↑ or P↓T↓ P 1 /T 1 =P 2 /T 2 or P/T=Constant

24. Combined Gas Law: (Temp is in Kelvin)

25. The volume of a “Get Well Soon” balloon is 2.5L at STP conditions. What would the volume of the balloon be on the moon (-93 0 C, 1.1x10 -8 kPa)

26. Quiz 14.2 A can of compressed air ruptures at an internal pressure of 225 lbs/in 2. At standard temperature (0.00 o C) the pressure is 55.5 lbs/in 2. At what temperature will the can burst (reach it bursting pressure)?

27. Ideal Gas Law PV=nRT Prairie Village is not a Real Town R= 8.31 ( LkPa)/(K mol) P, V, T n = moles R= 8.31 ( LkPa)/(K mol)

28. How many grams of He are needed to fill a weather balloon that is 2520L at sea level and 5.75 o C?

29. What is the pressure on the inside of a CO 2 cartridge? (There are 12.1 grams, the temperature in the room is 68.7F, and the volume is 15.9mL.) Would the pressure change if the room temperature changed?

30. PV=nRT X (0.0159L) = 0.275mol (8.31 L. kPa/mol. K) 293.4K 42,200 kPa or 42,169.33019 kPa about 417atm

31. Sample Problem

32. NaHCO 3 + HC 2 H 3 O 2  H 2 O +NaC 2 H 3 O 2 + CO 2 A classroom has a temperature of 303K and a pressure of 105kPa. What volume of CO 2 will be produced from 12.5g of NaHCO 3 ?

33. Quiz 14.3 How many moles of H 2 are needed to fill a balloon that is 2.50L, at sea level, and 295.75K? Extra credit – H 2 O + Na  NaOH + H 2 How many grams of Na will it take to fill the balloon?

34. Review

35. Properties of all gases When working with gases, there are 4 properties that must be considered: Gas Properties: Mass, Volume, Pressure, Temperature There are multiple equations: The properties that change determine the equation to select to solve for the unknown. All the remaining properties must be held constant.

36. Properties of all gases KNOW ALL THE FOLLOWING: Pressure at STP is: –1 atm = 760 mm Hg = 101.3 kPa = 14.7 lbs/in 2 Volume –1 mL = 0.001L = 1cm 3 Temperature at STP is 273 K (0° Celsius) –Use Kelvin (not Celsius)

37. Combined Gas Law: (Temp is in Kelvin)

38. Ideal Gas Law PV=nRT Prairie Village is not a Real Town R= 8.31 ( LkPa)/(K mol) P, V, T n = moles R= 8.31 ( LkPa)/(K mol)

39. Steps: 1. Known: Find the knowns. 2. Unknown: Find the unknowns. 3. Equation: Pick the equation that matches the knowns and unknowns. 4. Units: Make sure units are the same on both sides. T in Kelvin. 5. SigFig: Change the answer to the correct number of significant figures.