Applying Your Knowledge  Identify the phase changes in Figure 3-2 that are labeled a, b, and c.  Interpreting Graphics Describe the two phase changes represented in Figure 3-2 that can happen to a liquid.  Applying Concepts Which three phase changes in Figure 3-2 are endothermic?

Science Starter  Write on a piece of paper: Setting (leave room to answer) Characters (leave room to answer) Action (leave room to answer)  Read the Red Herring story below and fill in the blanks. Then write down 3 yes or no questions to ask me to solve the mystery.  STORY – Out for a drive, he stopped for gas, but when he filled up, the fuel indicator never budged. Why not?

EQ: “How are the volume, temperature, and pressure of gases related?” Gases Video

What measurements are important when studying gases?  Volume The amount of space that matter fills. Measured in cm3, mL, or L Since gas particles move and fill the space available, the volume of the gas is the same as the volume of its container.

What measurements are important when studying gases?  Temperature Temperature is a measure of the average energy of random motion of the particles of a substance. The faster the particles move – the greater the energy and the higher the temperature.

What measurements are important when studying gases?  Pressure Pressure of a gas is the force of its outward push divided by the area of the walls of the container. Measured in units of pascals (Pa or kPa) Pressure= Force Area Gas Volume & Pressure Video

Boyle’s Law

 1600’s, Boyle measured the volumes of gases at different pressures.  He found that when the pressure of a gas (at constant temperature) is increased, the volume of the gas decreases. When the pressure is decreased, the volume increases.  This relationship between pressure and volume of gas is called Boyle’s Law  Boyle’s Law Video Boyle’s Law Video

Practice  A machine exerts a force of 252 N on a piston having an area of m2. What is the pressure on the piston in Pa?  Pressure= 252N m2 = 586 Pa N= neutons (measures force) Pa=pascals (measures pressure)

Volume and Temperature  Jacques Charles (1700’s) found that when the temperature of a gas is increased at constant pressure, its volume increases.  When the temperature of a gas is decreased at constant pressure, its volume decreases.  This principle is called Charles’s Law  Simple Gas Law Video Simple Gas Law Video

Pressure and Temperature  When the temperature of a gas at constant volume is increased, the pressure of the gas increases.  When the temperature is decreased, the pressure of the gas decreases.

Boyle’s Law Application  What is the unit used for pressure? What is the pressure when the volume is 0.5 L? What is the pressure when the volume is 1.0 L?

Boyle’s Law Application  How would the graph change if the volume of the cylinder remained constant and temperature was the manipulated variable?

Boyle’s Law Application  Compare the collisions between particles of gas and the walls of a container when the volume of gas is 1.0 L and when the volume is 2.0 L. Assume the number of particles does not change. Explain any differences in collisions.

Boyle’s Law Application  If P 1 is p1 kPa and P 2 is p2 kPa, what are V 1 and V 2 ?

Summarizer EQ: “How are the volume, temperature, and pressure of gases related?”