1. Brittani Gerkin, Katie Whitfield, Cassie Myers, Landon Girle, Zachary Thomas, Dylan MacConnachie, and Ethan Manigbas Period 6

2. Pressure is the amount of force exerted per unit of area Kinetic theory- gas particles are constantly moving and colliding When gases are contained, the particles collide with the walls, exerting force Amount of force depends on size of container Collisions cause the walls of the container to move outward Ex. Balloon, tires Pressure is measured in pascals and kilopascals for larger numbers (kPa)

3. The atmosphere exerts pressure upon the earth’s surface Pressure changes throughout the different levels of the atmosphere Decreases the farther you go from Earth Pressure at sea level: 101.3 kPa Troposphere has the highest pressure Closest to Earth Highest temperature Exosphere has an extremely low pressure Farthest from Earth Lowest temperature

4. If an enclosed gas is heated, pressure increases Why? The particles begin to move faster (kinetic theory) and begin to strike the container walls faster and with more force If the container is flexible, like a balloon, the volume of the container will expand instead of the pressure increasing If it is not flexible, the container may not be able to withstand the pressure, and it might explode! If the volume of the container remains constant, an increase in temperature results in an increase in pressure

5. Robert Boyle (1627-1691) Boyle’s Law states that: if a gas is kept at a constant temperature, decreasing the volume will result in an increase in pressure. Increasing the volume will result in a decrease in pressure. Larger container= more room, less particle collisions, lower pressure Smaller container= less room, more particle collisions, higher pressure Weather balloons Inflated with low density gases As balloon rises, the atmospheric pressure decreases outside the balloon, so inside the balloon, the pressure increases Balloon expands

6. To use Boyle’s law you have to use the formula P₁V₁=P₂V₂ Initial Pressure (P₁) multiplied by Initial volume (V₁) =Final Pressure (P₂) multiplied by Final volume (V₂) It will remain constant if the temperature is constant. Example: A balloon has a volume of 10L and is at a pressure of 101kPa. When the pressure drops to 43kPa, what will the new volume be? P₁ = 101kPa, V₁ = 10L, P₂ = 43kPa, V₂ = ? Rearrange P₁V₁ = P₂V₂ to V₂ = P₁V₁/P₂ so that you can find the final volume V₂ = (101kPa)(10L)/43kPa = 23.5L When the pressure drops to 43kPa, the volume of the gas will increase to 23.5L

7. Charles’s Law states that: if a gas is kept at a constant pressure, a temperature increase will result in an increase in volume of the gas (and of the container if possible. If not, it might explode) Why? Aforementioned pressure-temperature relationship If pressure is constant, Increase in temperature= increase in volume of gas Decrease in temperature= decrease in volume of gas Absolute zero= -273 degrees Celsius, temperature at which the volume of a gas becomes zero If a gas reaches it’s own specific boiling point, it will become a liquid

8. V₁/T₁=V₂/T₂ Temperature must be in Kelvin Initial volume (V₁) divided by initial temperature (T₁) equals final volume (V₂) divided by final temperature (T₂) The pressure must remain constant Ex. A 2L balloon at 25 degrees Celsius is placed into a container of ice water that is 3 degrees Celsius. What is the final volume? Convert temperature from Celsius to Kelvin by adding 273 V₁ = 2L, T₁ = 298 K, V₂ = ?, T₂ = 276 K Rearrange V₁/T₁=V₂/T₂ to V₂ = (V₁)(T₂)/T₁ (2L)(276K)/298K = 1.9L When the temperature drops to 3 degrees Celsius, the volume of the gas will decrease to 1.9L