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Q of the Day. DAY 2 11-15. At 300 K a sample of gas occupies 5 L, if the volume is decreased to 2 L what is the new temperature?. V 1 /T 1 = V 2 /T 2. Key Concepts.
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Q of the Day DAY 2 11-15 At 300 K a sample of gas occupies 5 L, if the volume is decreased to 2 L what is the new temperature? V1/T1 = V2/T2
Key Concepts • Particles in a gas are considered to be small, hard spheres with an insignificant volume. The motion of the particles in a gas is ______, ________, and __________. All collisions between particles in a gas are perfectly ________. • Gas __________ is the result of billions of rapidly moving particles in a gas simultaneously colliding with an object. • The Kelvin temperature of a substance is ________ ______________ to the average kinetic energy of the particles of the substance. rapid random constant elastic pressure directly proportional
Kinetic-molecular Theory - Gases 1. Gases consist of large #s of tiny particles that are far apart relative to their size (each particle has mass) 2. Collisions between gas particles and between particles and container walls are elastic 3. Gas particles are in constant, rapid, random motion… they possess kinetic energy
Kinetic-molecular Theory - Gases 4. There are no forces of attraction or repulsion between gas particles • The average kinetic energy of gas particles depends on the temperature of the gas
Whose Law P1/T1 = P2/T2 P1V1 = P2V2 V1/T1 = V2/T2 Gay-Lussac’s Boyle’s Charles’
A MOLE How much is a mole of water? How could we measure out one mole of water (in this lab)? How much is one mole of air? How could we measure out one mole of air (in this lab)?
The Gas Laws The Gas Laws Dalton’s Law of Partial Pressures: – the total pressure of a mixture of gases is equal to the sum of the partial pressures of the component gases. PT = P1 + P2 + P3 + P4 …
The Gas Laws Oxygen is collected by water displacement at 35°C. The total pressure of gases is 321 mm Hg. What is the pressure of the oxygen? (the pressure of water vapor at 35°C is 23.8 mm Hg)
The Gas Laws If a sample of gas contains CO2, O2, and CO, and you know the pressure of O2 is 200. mm Hg, and the pressure of CO is 250 mm Hg, what is the pressure of CO2, if the total pressure is 700. mm Hg?
The Gas Laws If a sample of gas contains CO2, O2, and CO, and you know the pressure of O2 is 0.5 atms., and the pressure of CO is 20260 Pa, what is the pressure of CO2, if the total pressure is 760. mm Hg? If a sample of gas contains CO2, O2, and CO, and you know the pressure of O2 is 0.5 atms., and the pressure of CO is 20260 Pa, what is the pressure of CO2, if the total pressure is 760. mm Hg?
Assignment Homework # 1 Unit 4 - Due Wed. 11-16 # 5 A 7.0 L gas sample at STP is compressed to a volume of 2.0 L, and the temperature is increased to 320 K. What is the new pressure of the gas in Pa?
The Combined Gas Law • How are the pressure, volume, and temperature of a gas related? The Combined Gas Law
P1 V1 P2 V2 = T1 T2 The Combined Gas Law • There is a single expression, called the combined gas law, that combines Boyle’s law, Charles’s law, and Gay-Lussac’s law.