3.2 Continued Key Concept How are the temperature, volume, and pressure of a gas related?

In 1787, the French scientist Jacques Charles discovered the relationship between the _______________ and ______________ of a gas at a constant pressure while doing work with hot air balloons temperature volume

When temperature decreases, gas particles will move ___________ and collide ________ often with the walls of their container….causing a balloon to _____________ When temperature increases, gas particles will move _____________ and collide more ______ with the walls of their container…causing a balloon to ____________ slower less shrink faster often expand

So at a constant pressure, volume is ______________ proportional to temperature in ________________ directly kelvins So if temperature increases, what will happen to volume? And if temperature decreases, what will happen to volume? increase decrease

The line on the graph is dashed as you move towards 0 K, also called ____________ ______, because volume can ____________ disappear and particles will always move just a _________ bit. absolute zero never tiny

Think carefully, can an item like a potato expand very much? So why do you think people often poke holes in the skin of a potato before they heat it? No! To reduce pressure

Charles’s law only works for items that allow volume to __________ while keeping pressure constant change

The equation for Charles’s law is… V1= V2 = Hint….Charles is a television star V1 V2 = T2 T1 initial temperature final temperature initial volume final volume

Practice!...If the temperature of a gas is doubled, what should happen to the volume of a gas? If the temperature increases from 20 kelvin to 40 kelvin, what would the volume of 10 mL gas change to? increase 40 K 10 mL x _________ 20 K = 20 mL

Boyle’s Law: Pressure and Volume Robert _________ (1627-1691), was the first to describe the relationship between the volume and pressure of a gas, at constant _____________ Boyle temperature

number of gas particles changing? Recall that adding pressure to a gas, similar to squeezing a balloon, can compress a confined gas into a _____________ volume Is the actual amount or number of gas particles changing? smaller No!

According to the data shown, what happens to volume as pressure increases? Because the changes in pressure and volume are always _____________, their relationship is an ___________ proportion Volume decreases opposite inverse

At a constant temperature, the pressure exerted by a gas depends on the ____________ of ______________ between gas particles and the container. number collisions If the same number of ____________ are squeezed into a __________space, the frequency of collisions __________, thereby increasing the pressure. particles smaller increases

Practice!...If the pressure of a gas is doubled, what should happen to the volume of a gas? If the pressure increases from 1.0 atm to 2.0 atm, what would the volume of 10 mL gas change to? decrease 1.0 atm 10 mL x _________ 2.0 atm = 5 mL

In mathematical terms, this law is expressed as follows. Boyle’s Law In mathematical terms, this law is expressed as follows. P1 = P2 = V1= V2 = Initial pressure Final pressure Initial volume Final volume

Vacuum Pump Demonstration The vacuum pump will remove the air inside the glass chamber, _____________ pressure on the balloon Predict what will happen to the size of the balloon. Were you correct? Did the temperature of the room change during this demonstration? reducing Increased! no

The Combined Gas Law The relationships described by Boyle’s law and Charles’s law can be described by a single law. The _______________ gas law describes the relationship among the temperature, volume, and pressure of a gas when the number of particles is constant. combined

Assessment Questions What causes the pressure to increase if more gas particles are added to a closed container? an increase in the number of collisions between the gas and the container walls a decrease in the volume of the container a decrease in the size of each particle as the number of particles increases an increase in the number of collisions between air particles and the outside of the container

Assessment Questions When first blown up, a balloon is firm because of the air pressure inside it. However, after time, the balloon becomes soft as the air pressure inside drops. What could have caused the air pressure to decrease? increase in air temperature decrease in the balloon's volume decrease in the number of air particles as they leaked out of the balloon a chemical reaction between the air particles and the balloon

3. According to Charles’s law, the relationship Assessment Questions 3. According to Charles’s law, the relationship between the temperature and the volume of a gas is… direct. inverse. exponential. inverse square.

Assessment Questions When the temperature of a gas in a closed container is increased, the pressure increases. True False