Ch. 16 Sect. 3: Behaviors of Gases & Gas Laws BOYLE’S LAW & CHARLES’ LAW

Review __________ results from gas particles __________ with the walls of their container Pressure is ______ divided by _____  High pressure = _____________  Low pressure = _____________ Measured in units of: Pascal’s (Pa) kilopascals (kPa) atmospheres (atm) millimeters mercury (mm Hg)

Variables that Affect Gases There are four variables that we need to consider when looking at the properties of gases: 1. _________________(number of _______________) 2. __________ (number of __________ in a certain area) 3. __________ (amount of __________ it takes up) 4. __________ (average _________ energy of particles)

Robert Boyle ( , Ireland) One of the founders of modern chemistry He made improvements to the construction of an air pump w/the assistance of Robert Hooke; he used this to do experiments on the properties of air Boyle’s Law originally published in 1662

Boyle’s Law What is the relationship between pressure and volume of a gas? “The pressure of a fixed amount of gas varies ____________ with the volume of that gas” Or If the pressure goes up, the volume goes ____! This applies as long as the temperature remains constant as well.

Explaining Boyle’s Law If pressure increases, that means the number of __________ must also be increasing.  By decreasing the volume of a container, the number of collisions will ________ This occurs only if the temperature and amount of gas remain constant Boyle's Law Animation

Boyle’s Law In Action When applied to a real life situation, we find that the pressure multiplied by the volume is always equal to a ____________ value  The product of the initial volume and pressure will equal the product of the final volume and pressure P 1 V 1 = P 2 V 2

Boyle’s Law Practice Problem 1 If a balloon has a volume of 500 mL at a pressure of 1-atm, and is driven into the mountains at a pressure 0.5-atm, what is the new volume of the balloon? Givens Formula Solution

Boyle’s Law Practice Problem 2 A balloon has a volume of 10.0 L at a pressure of 101 kPa. What will the new pressure be when the volume is increased to 23.5 L? Givens Formula Solution

More Boyle’s Law Practice Complete the following table using the Boyle’s Law formula. P 1 (kPa) V 1 (mL) P 2 (kPa) V 2 (mL) Work

Review What are the variables that affect gases? In Boyle’s Law, which variables remain constant, and which variables change? Constants: Variables:

Jacques Charles ( , French) Made the first flight of a hydrogen balloon Inventor—valve to let H out of balloon, hydrometer Confirmed Ben Franklin’s electrical experiments 1787 discovered Charles’ Law

Charles’s Law What is the relationship between temperature and volume of a gas? “The volume of a fixed amount of gas varies ________ with the temperature of that gas” Or… If the temperature goes up, the volume goes ________! This applies as long as the pressure remains constant as well.

Explaining Charles’s Law If the temperature increases, that means the average _______ energy of the particles also increases.  Particles with more kinetic energy move more quickly and strike the walls of the container more often with more force which causes the volume to ________ (because the walls expand, pressure does not increase) This occurs only if the pressure and amount of gas remain constant Charles's Law Animation

Charles’s Law In Action When applied to a real life situation, we find that the volume divided by the temperature is always equal to a ________ value  The quotient of the initial volume and temperature will equal the quotient of the final volume and temperature V 1 = V 2 T 1 T 2 In order to avoid having negative values, temperatures need to be converted into ___________ ° C = K K – 273 = ° C

Charles’s Law Practice Problem 1 If a balloon has a volume of 500 mL at 20 o C, and is heated to 80 o C what will its volume become? Givens Formula Solution

Charles’s Law Practice Problem 2 If a balloon has a volume of 2.0 L at 25 o C, and it’s volume is decreased to 1.9 L, what is the new temperature in degrees Celsius? Assume pressure and amount of gas remains constant. Givens Formula Solution

More Charles’ Law Practice V 1 (mL) T 1 (K) V 2 (mL) T 2 (K) Work Complete the following table using the Charles’s Law formula.