1. Warm-up 6-1 Convert -121°C to Kelvins
(2) The graph represents a reaction
Is this reaction exothermic or endothermic?
(3) STP is (a) ° C and 1 atm
(b) 0° C and 1atm
(c ) 0° C and 780 mmHg
(d) 273 ° C and kPA

2. Answers to Warm-up 6-1 Convert -121°C to Kelvins Answer: 152 Kelvins
(2) The graph represents a reaction
Is this reaction exothermic or endothermic?
Answer: endothermic
(3) STP is (a) ° C and 1 atm
(b) 0° C and 1atm
(c ) 0° C and 780 mm Hg
(d) 273 ° C and kPA
Answer: (b) 0° C and 1atm

3. Some Tips in Solving Gas Law Problems
GAS LAWS
Some Tips in Solving Gas Law Problems

4. REMEMBER: Convert.. Convert… Add 273 to Celsius
All temps must be in Kelvin
Convert..
Convert…
Add 273 to Celsius

5. USE THE UNITS! Ans: Pressure
Remember that the units can be used to identify given information.
(1) kPA (kiloPascal)
Ans: Pressure
(2) L (Liter)
Ans : Volume

6. Ans : Volume Ans : Pressure (3) K (Kelvin) Ans: Temperature (4) torr
(5) Pa (Pascal)
Ans : Pressure
(6) mL (milliliter)
Ans : Volume

7. Ans: Pressure (7) mm Hg (millimeter mercury) Ans : Pressure
(8) atm (atmosphere)
(9) cm Hg (centimeter mercury)
Ans: Pressure

8. Ans : Pressure Ans: Temperature (10) ft3 (cubic feet) Ans : Volume
(11) psi (pounds per square inch)
Ans : Pressure
(9) °C (Celsius)
Ans: Temperature

9. Remember the relationships between the variables (and don’t forget the constant!)

10. (constant temperature)
Boyle’s Law
(constant temperature)
Pressure Volume
P1V1 = P2V2

11. Charles Law (constant pressure)
Kelvin Volume
Temperature
V1T2 = V2T1

12. Gay-Lussac’s Law (constant volume)
Kelvin Pressure
Temperature
P1T2 = P2T1

13. Combined Gas Law
(no constant)
P1V1T2 = P2V2T1

14. …Let’s see if you can recognize the gas law for each of these problems…
The Celsius temperature of a 3.00 L sample of a gas was lowered from 80.0C to 30.0C. What will be the resulting volume of this gas? Charles Law

15. A gas in a sealed container has a pressure of 125 kPa at a temperature of 30.0C ? If the pressure in the container is increased to 201 kPa, what is the new temperature?
Gay-Lussac’s law

16. A sample of gas occupies a volume of 1. 35 L at 27C
A sample of gas occupies a volume of 1.35 L at 27C. What temperature is required to increase the volume to 3.00L ?
Charles law

17. A sample of helium gas has a volume of 250 mL at 740 torr pressure
A sample of helium gas has a volume of 250 mL at 740 torr pressure. Find its volume at 800 torr pressure if the temperature of the helium was not changed.
Boyle’s law

18. Neon gas occupies 2 L at 135 kPa
Neon gas occupies 2 L at 135 kPa. Find the pressure that this gas will exert if its volume was lowered to 1.75 L (assuming constant temperature).
Boyle’s law

19. At 0. 00°C and 1. 00 atm pressure, a gas has a volume of 30. 0 mL
At 0.00°C and 1.00 atm pressure, a gas has a volume of 30.0 mL.If the temperature is raised to 30.0°C and the gas is transferred to a 20.0 mL container, what will be the gas pressure in the container? Combined gas law

20. Helium gas in a 2. 00 L sealed metal cylinder is under 1. 12 atm
Helium gas in a 2.00 L sealed metal cylinder is under 1.12 atm. pressure. At C, that same gas sample has a pressure of atm. What was the initial temperature of the gas in the cylinder?
Gay – lussac’s law

21. A 25. 0–L sample of an ideal gas at STP is heated to 55°C at 605 torr
A 25.0–L sample of an ideal gas at STP is heated to 55°C at 605 torr. What is the new volume?
Combined gas law