Lon-Capa

1st HW assignment due Friday, 9/4, 5 pm. It is open now.

1st Quiz due Sunday, 9/6 by 10 pm.

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For Wednesday Continue working on Lon-Capa. Continue reading Chapter 5 and

doing the Chapter 5 homework. See me or email me if there are

any questions or concerns.

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Studying Gases Good way to study the process of

science. Distinguish between laws (what)

and theories (why). Make observations. Use observations to develop

theories. Make more observations. Continue. 3

Gases – Macroscopic Observations

Gases take up the volume of the container. 1 cup of helium? Compressible

Gases mix well (diffusion). We can smell ammonia, vinegar, etc.

Gases exert pressure. Basketballs, bike tires, etc. Explosions

Density of a gas changes greatly with temperature.

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Clicker Question You are holding two balloons filled with air – a large balloon and a small balloon. What can be said about the relative pressure of air in each balloon?

a) The pressure in the larger balloon is greater because there are more moles of gas.

b) The pressure in the smaller balloon is greater because there is less space inside the balloon.

c) The balloons have essentially the same pressure.

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V and n (KMT)

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V and T (KMT)

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V vs. T(°C) (constant P, n)

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V vs. T(K) (constant P, n)

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P and V (KMT)

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P vs. V (constant n, T)

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PV/nT for Different Gases

(all at 1 atm and 273K)

O2: 0.082040 Latm/molKN2: 0.082059 Latm/molKCO2: 0.081538 Latm/molKNH3: 0.080875 Latm/molKAr: 0.082040 Latm/molK

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Kinetic Molecular Theory Gases consist of particles in

constant random motion. Temperature is a measure

of average kinetic energy. Pressure is due to collisions

of gas particles with the container.

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Clicker Question You are holding three balloons, each containing an equal mass of a different gas, and each gas acting ideally. The balloon containing which gas is the largest balloon?

a)H2

b)Hec)O2

d) All have the same volume.14