Introduction to Chemistry Chapter 2 Lesson 3 Gas Behavior Introduction to Chemistry Chapter 2 Lesson 3

Objectives 1. Explain how pressure and temperature are related. 2. Explain how volume and temperature of a gas are related. 3. Explain how pressure and volume of a gas are related. We are covering NGSS DCI-MS-PS1.A.6 The changes of state that occur with variations in temperature or pressure can be described and predicted using these models of matter. PE-MS-PS1-4 Develop a model that predicts and describes changes in particle motion, temperature, and state of a pure substance when thermal energy is added or removed.

Jacques Charles Planet Diary French scientist Jacques Charles is best known for his work on gases. But he also made contributions to the sport of ballooning. On August 27, 1783, Charles released the first hydrogen-filled balloon, which was about 4 meters in diameter. This balloon, which did not carry any people, rose to a height of 3,000 feet. Charles also improved the design of hot-air balloons. He added a valve line that allowed the pilot to release gas from the balloon. He also added a wicker basket that attached to the balloon with ropes. Charles was elected to the French Academy of Sciences in 1785.

Gas Laws https://www.pearsonrealize.com/commu nity/program/b5aea82b-ad2c-3447-b122- 4b953e6a7cba/17/tier/b48bdcf2-b3e9- 3faa-9f9e- 5e920e930248/18/lesson/3cd791e3- c3c8-3d43-9892- 980c350feedc/18/content/fb1a63a9- 8657-3f76-833f-e752222d9d6f/19

How Are Pressure and Temperature of a Gas Related? Recall that the higher the temperature of a substance, the faster its particles are moving on average. The faster gas particles move, the more frequently they collide with the walls of their container and the greater the force of the collisions. 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. This explains why truck (and sometimes car) tires burst on a long drive on a very hot day.

Gas Behavior Temperature and Gas Pressure When a gas is heated in a closed, rigid container, the particles move faster and collide more often. How would the change in pressure of the gas be shown on each pressure gauge?

Gay-Lussac's Law: The temperature of a gas is directly proportional to its pressure.

How Are Volume and Temperature of a Gas Related? When the temperature of a gas is increased at constant pressure, the volume increases. When the temperature of a gas is decreased at constant pressure, its volume decreases. This principle is called Charles’s law. When the volume of a gas at constant pressure is graphed as compared to its temperature, the graph is a straight line that passes through the origin. This shows that the variables volume and pressure have a directly proportional relationship—one variable is equal to the product of a constant and the other variable.

Gas Behavior Cooling a Balloon The volume of a gas-filled balloon decreases as temperature decreases and then increases as temperature increases.

Gas Behavior Charles’s Law How would the gas particles and piston look at the different higher temperatures?

Gas Behavior Temperature and Gas Volume The data shown in the table are plotted on the graph.

How Are Pressure and Volume of a Gas Related? 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 is called Boyle’s law. If the relationship between the pressure and the volume of a gas, at constant temperature, is graphed, the result is a curve. A high pressure corresponds to a low volume and a low pressure corresponds to a high volume. The product of the variables pressure and volume is a constant. The pressure and volume are inversely proportional to each other.

Gas Behavior Boyle’s Law As weights are added to the top of each piston, the piston moves farther down in the cylinder. Rank the pressure and the volume in each of the cylinders.

Gas Behavior Graphing Boyle’s Law Use the data to make a line graph. What would be a good title for the graph?

How Are Pressure and Volume of a Gas Related?

Gas Laws Summary

Combined Gas Law When we put Boyle's law, Charles' law, and Gay- Lussac's law together, we come up with the combined gas law, which shows that: Pressure is inversely proportional to volume, or higher volume equals lower pressure. Pressure is directly proportional to temperature, or higher temperature equals higher pressure. http://study.com/academy/lesson/combined-gas-law-definition- formula-example.html