Sections 1 & 2

Section 13-1 Section 13.1 The Gas Laws State the relationships among pressure, temperature, and volume of a constant amount of gas. scientific law: describes a relationship in nature that is supported by many experiments Apply the gas laws to problems involving the pressure, temperature, and volume of a constant amount of gas. Explain the difference between a law & a theory?

Section 13-1 Section 13.1 The Gas Laws (cont.) Boyle’s law absolute zero Charles’s law Gay-Lussac’s law combined gas law For a fixed amount of gas, a change in one variable—pressure, temperature, or volume—affects the other two. What is a variable?

Section 13-1 Boyle's Law Boyle’s law states that the volume of a fixed amount of gas held at a constant temperature varies inversely with the pressure.Boyle’s law P 1 V 1 = P 2 V 2 where P = pressure and V = volume Give an everyday example of Boyle’s Law.

Section 13-1 Charles's Law As temperature increases, so does the volume of gas when the amount of gas and pressure do not change. Kinetic-molecular theory explains this property. Draw a series of cartoons to show what happens to a filled helium balloon as the temperature gradually increases.

Section 13-1 Charles's Law (cont.) What type of mathematical relationship is V vs T ?

Section 13-1 Charles's Law (cont.) Absolute zero is zero on the Kelvin scale.Absolute zero Charles’s law states that the volume of a given amount of gas is directly proportional to its kelvin temperature at constant pressure.Charles’s law Why must all temperatures be put into Kelvin units when using gas laws?

Section 13-1 Gay-Lussac's Law Gay-Lussac’s law states that the pressure of a fixed amount of gas varies directly with the kelvin temperature when the volume remains constant.Gay-Lussac’s law How does Gay-Lussac’s Law apply to NASCAR racing teams?

Section 13-1 Gay-Lussac's Law (cont.) What type of mathematical relationship is P vs T ?

Section 13-1 If all three laws (Boyle’s, Charles’, Gay- Lussac’s) are combined then the resulting equation is the: combined gas law states the relationship among pressure, temperature, and volume of a fixed amount of gas. The Combined Gas Law In the combined gas law formula, draw a circle around Boyles’ Law, Charles’ Law & Gay- Lussac’s Law. Shade in each circle a different color to distinguish the individual laws that make up the combined law.

When using the combined gas law, cross out any unnecessary variable. Ex) A child’s party inflatable has a pressure of 15.8 atm at the beginning of the party when the temperature is 33 o C. Near the end of the party the temperature drops to 17 o C. What is the new pressure? 1 st : Convert Celsius temperatures to Kelvin units. Solution: T 1 = = 306 KT 2 = = 290. K The Combined Gas Law (cont.)

2 nd : Substitute values into equation atm V K = P 2 V K 3 rd : Cross out any variables not mentioned at all. 4 th : Cross multiply & solve for the unknown. (15.8atm) (290. K)= (306 K) P K P 2 = 15.0 atm The Combined Gas Law (cont.)

Section 13-1 The Combined Gas Law (cont.)