15-2 Behavior of Gases 15-3 Graphing Gas Behavior

Measuring Gases Volume – the amount of space matter fills Measured in cm3, mL, L Volume of a gas is the same as the volume of its container Temperature – measure of the energy of motion of particles Faster = higher temperature Pressure – an outward push of a gas on the walls of a container Pressure = Force/ Area

Relating Pressure & Volume Boyle’s Law If pressure of a gas is increased = the volume of the gas decreases If the pressure of a gas is decreased = the volume of the gas increases

Relating Pressure & Temperature If increase temperature of a gas = increase in pressure If decrease temperature of a gas = decrease in pressure On long trips truck tires heat up and the pressure increases and the tire can pop

Relating Volume & Temperature Charles’s Law When temperature of a gas increases = the volume increases When temperature of a gas decreases = the volume decreases Basketball left out overnight in cold becomes soft because volume of air inside decreased

Graphing Gas Behavior X – axis is horizontal Y –axis is vertical Graph manipulated variable on x-axis Y –axis is vertical Graph responding variable on y-axis Label each axis with the name of the variable, the units used, and the range of variables

Directional Proportional Graphs If a graph shows a straight line passing through point 0,0 the variables are directional proportional to each other Ex. Charles’s Law

Inversely Proportional Graphs When a graph forms a curve, the variables vary inversely with each other. Ex. Boyle’s Law