Experience Chemistry Lesson 9.2.1: Gas Laws

​Lesson 9.2.1: The Gas Laws

The Kelvin Temperature scale is used when working with gas laws

• Convert from Celsius by adding 273 to your temperature

  • 0 ° C = 273 K

  • 100 ° C = 373 K

Gases also tend to be studied under Standard Temperature and Pressure Conditions (STP)

• 1 atm Pressure

• ​0 ° Celsius

​

Note for Gas Law Equations

​

Boyle's Law

• Discovered by Robert Boyle

• When the temperature and number of particles are held constant, the volume varies inversely with the pressure.

  • As Volume increases, pressures decreases​

• P₁ ×​ V₁ = P₂ × V₂

  • The units for Pressure and volume don't matter as long as they are the same on both sides of the equation!​

Experience Chemistry | Lesson 9.2 Part 1

Boyle's Law Sample Problem 1

• A Ballon Contains 30.0 L of Helium gas at a pressure of 103 kPa. What is the volume of the helium when the balloon rises to an altitude where the pressure is only 25.0 kPa (assume the temperature is constant)

  • Step 1​: Identify the knowns

    • V₁= 30 L

    • P₁₌ 103 kPa

    • V₂ =?

    • P₂=25 kPa

  • Step 2: Plug your numbers into the equation

    • 30 x 103 = 25 x V₂

    • V₂= (30 x 103) / 25

Experience Chemistry | Lesson 9.2 Part 1

Fill in the Blanks

A Ballon Contains 30.0 L of Helium gas at a pressure of 103 kPa. What is the volume of the helium when the balloon rises to an altitude where the pressure is only 25.0 kPa (assume the temperature is constant)

Boyle's Law Sample Problem 2

• A gas with a volume of 4.00 L at a pressure of 205 kPa is allowed to expand to a volume of 12.0 L. What is the pressure in the container if the temperature remains constant?

  • Step 1​: Identify the knowns

    • V₁=

    • P₁₌

    • V₂ =

    • P₂=

  • Step 2: Plug your numbers into the equation

Experience Chemistry | Lesson 9.2 Part 1

Boyle's Law Sample Problem 2

• A gas with a volume of 4.00 L at a pressure of 205 kPa is allowed to expand to a volume of 12.0 L. What is the pressure in the container if the temperature remains constant?

  • Step 1​: Identify the knowns

    • V₁= 4.00 L

    • P₁₌ 205 kPa

    • V₂ = 12.0 L

    • P₂= ?

  • Step 2: Plug your numbers into the equation

    • 4 x 205 = 12 x P₂

    • P₂₌ (4 x 205)/12

Experience Chemistry | Lesson 9.2 Part 1

Fill in the Blanks

A gas with a volume of 4.00 L at a pressure of 205 kPa is allowed to expand to a volume of 12.0 L. What is the pressure in the container if the temperature remains constant? **Round to two decimal Places**

Boyle's Law Sample Problem 3

• A Sample of Oxygen Gas has a Volume of 150.0 mL when its Pressure is 0.947 atm. What will the volume of the gas be at 0.987 atm if the volume of the gas remains constant?

  • Identify what we have

    • V₁=

    • P₁=

    • V₂ =

    • P₂ =

Experience Chemistry | Lesson 9.2 Part 1

Boyle's Law Sample Problem 3

• A Sample of Oxygen Gas has a Volume of 150.0 mL when its Pressure is 0.947 atm. What will the volume of the gas be at 0.987 atm if the volume of the gas remains constant?

  • Identify what we have

    • V₁= 150

    • P₁=0.947

    • V₂ = ?

    • P₂ =0.987

  • Plug our Values into Boyle's Law

    • 150 x 0.947 = V₂ x 0.987 ​

Experience Chemistry | Lesson 9.2 Part 1

Fill in the Blanks

 

A Sample of Oxygen Gas has a Volume of 150.0 mL when its Pressure is 0.947 atm. What will the volume of the gas be at 0.987 atm if the Temperature of the gas remains constant? Round to 2 Decimal places

Fill in the Blanks

Use Boyle's Law to solve for the missing value

V₁= 2 x 10⁵ L, P₁=? V₂ = 1.8 x 10^3, and P₂ = 180 mm Hg Round to 2 Decimal Places

Fill in the Blanks

A Balloon Filled with Helium gas has a volume of 500 mL at a pressure of 1 atm. The balloon is released and reaches an altitude where the pressure is 0.5 atm. If the temperature has remained the same, what volume does the gas occupy at this height?

Charles's Law

Experience Chemistry | Lesson 9.2 Part 1

Charles's Law Sample Problem 1

Experience Chemistry | Lesson 9.2 Part 1

​A Sample of neon Gas occupies a volume of 752 mL at 25° C. What will the Volume be at 50° C if the pressure remains constant?

• Step 1: Identify what we know

  • V₁= 752 mL

  • T₁= 25°​C

  • V₂=?

  • T₂= 50°C

Charles's Law Sample Problem 1

Experience Chemistry | Lesson 9.2 Part 1

​A Sample of neon Gas occupies a volume of 752 mL at 25° C. What will the Volume be at 50° C if the pressure remains constant?

• Step 1: Identify what we know

  • V₁= 752 mL

  • T₁= 25°​C

  • V₂=?

  • T₂= 50°C

• Step 2 Change Temperatures to Kelvin

  • T₁= 25 + 273

  • T₂= 50 + 273

Charles's Law Sample Problem 1

Experience Chemistry | Lesson 9.2 Part 1

​A Sample of neon Gas occupies a volume of 752 mL at 25° C. What will the Volume be at 50° C if the pressure remains constant?

• Step 1: Identify what we know

  • V₁= 752 mL

  • T₁= 25°​C

  • V₂=?

  • T₂= 50°C

• Step 2 Change Temperatures to Kelvin

• Step 3: Plug Values into our Equation and solve for our unknown

Fill in the Blanks

A Sample of neon Gas occupies a volume of 752 mL at 25° C. What will the Volume be at 50° C if the pressure remains constant? **Round to Two Decimal Places**

Charles's Law Sample Problem 2

Experience Chemistry | Lesson 9.2 Part 1

• A balloon filled with Oxygen gas occupies a volume of 5.5 L at 25°C. What Volume will the balloon be at 100°C?

  • Identify what we know

    • V₁= 5.5 L

    • T₁= 25°​C + 273 = 298

    • V₂=?

    • T₂= 100°C+273 =373 K

  • Step 3: Plug Values into our Equation and solve for our unknown

Fill in the Blanks

A balloon filled with Oxygen gas occupies a volume of 5.5 L at 25°C. What Volume will the balloon be at 100°C? **Round to 2 Decimal Places**