Gas Laws Studies of the behavior of gases played a major role in the development of physical sciences in the 7 th and 8 th centuries.

Boyle’s Law Robert Boyle was among the first to note a relationship between pressure and volume of a gas. He measured the volume of air at different pressures, and observed a pattern of behavior. During his experiments temperature and amount of gas never changed Robert Boyle was among the first to note a relationship between pressure and volume of a gas. He measured the volume of air at different pressures, and observed a pattern of behavior. During his experiments temperature and amount of gas never changed

Boyle’s Law Boyle found that as pressure increases, volume decreases. For example: Boyle found that as pressure increases, volume decreases. For example:

Boyle’s Law Because we know: as pressure increases, volume decreases, we also know that as pressure decreases, volume increases. This is known as an inverse relationship (as one variable increases, the other decreases) Because we know: as pressure increases, volume decreases, we also know that as pressure decreases, volume increases. This is known as an inverse relationship (as one variable increases, the other decreases)

As the pressure increases Volume decreases Volume decreases

How does Pressure and Volume of gases relate graphically? Temperature, # of particles remain constant Temperature, # of particles remain constant Volume Pressure As pressure increases, volume decreases.

Charles’s Law Jacques Charles determined the relationship between temperature and volume of a gas. He measured the volume of air at different temperatures, and observed a pattern of behavior. During his experiments pressure of the system and amount of gas were held constant. Jacques Charles determined the relationship between temperature and volume of a gas. He measured the volume of air at different temperatures, and observed a pattern of behavior. During his experiments pressure of the system and amount of gas were held constant.

Charles’s Law Charles found that as temperature increases, volume increases. For example: A helium balloon during summer: A helium balloon is blown up inside a store. After spending a few hours outside in the sun the balloon begins to expand (volume increases). Charles found that as temperature increases, volume increases. For example: A helium balloon during summer: A helium balloon is blown up inside a store. After spending a few hours outside in the sun the balloon begins to expand (volume increases).

Volume of balloon at 25° C Volume of balloon at -5°C

Charles’s Law Because we know: as temperature increases, volume increases, we also know that as temperature decreases, volume decreases. This is known as a direct relationship (the variables increase and decrease together). Because we know: as temperature increases, volume increases, we also know that as temperature decreases, volume decreases. This is known as a direct relationship (the variables increase and decrease together).

How does Temperature and Volume of gases relate graphically? Pressure and the # of particles remain constant Pressure and the # of particles remain constant Temp Volume As temperature increases, volume increases. As temperature decreases, volume decreases. REMEMBER: Volume is the amount of space matter takes up. REMEMBER: Volume is the amount of space matter takes up.