Ch 10 11 Gases II The Gas Laws

Ch. 10 & 11 - Gases II. The Gas Laws (p. 313 -322)

A. Boyle’s Law PV = k P V

A. Boyle’s Law b The pressure and volume of a gas are inversely related • at constant mass & temp PV = k P V

A. Boyle’s Law

B. Charles’ Law V T

B. Charles’ Law b The volume and absolute temperature (K) of a gas are directly related • at constant mass & pressure V T

B. Charles’ Law

C. Gay-Lussac’s Law P T

C. Gay-Lussac’s Law b The pressure and absolute temperature (K) of a gas are directly related • at constant mass & volume P T

D. Combined Gas Law P V PV PV = k T P 1 V 1 P 2 V 2 = T 1 T 2 P 1 V 1 T 2 = P 2 V 2 T 1

E. Gas Law Problems b. A gas occupies 473 cm 3 at 36°C. Find its volume at 94°C. CHARLES’ LAW GIVEN: T V V 1 = 473 cm 3 T 1 = 36°C = 309 K V 2 = ? T 2 = 94°C = 367 K WORK: P 1 V 1 T 2 = P 2 V 2 T 1 (473 cm 3)(367 K)=V 2(309 K) V 2 = 562 cm 3

E. Gas Law Problems b. A gas occupies 100. m. L at 150. k. Pa. Find its volume at 200. k. Pa. BOYLE’S LAW GIVEN: P V V 1 = 100. m. L P 1 = 150. k. Pa V 2 = ? P 2 = 200. k. Pa WORK: P 1 V 1 T 2 = P 2 V 2 T 1 (150. k. Pa)(100. m. L)=(200. k. Pa)V 2 = 75. 0 m. L

E. Gas Law Problems b. A gas occupies 7. 84 cm 3 at 71. 8 k. Pa & 25°C. Find its volume at STP. COMBINED GAS LAW GIVEN: P T V WORK: V 1 = 7. 84 cm 3 P 1 V 1 T 2 = P 2 V 2 T 1 P 1 = 71. 8 k. Pa (71. 8 k. Pa)(7. 84 cm 3)(273 K) T 1 = 25°C = 298 K =(101. 325 k. Pa) V 2 (298 K) V 2 = ? P 2 = 101. 325 k. Pa V 2 = 5. 09 cm 3 T 2 = 273 K

E. Gas Law Problems b. A gas’ pressure is 765 torr at 23°C. At what temperature will the pressure be 560. torr? GAY-LUSSAC’S LAW GIVEN: P T WORK: P 1 = 765 torr P 1 V 1 T 2 = P 2 V 2 T 1 = 23°C = 296 K (765 torr)T 2 = (560. torr)(296 K) P 2 = 560. torr T 2 = 216 K = -57°C T 2 = ?