Chem - Ch 13.1, 14 Flashcards

1
Q

What are the 3 assumptions of kinetic theory as it applies to gases

A

particles in a gas are considered to be small hard spheres with an insignificant volume
motion of particles in a gas is rapid, constant, and random
all collisions between particles in a gas are perfectly elastic

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2
Q

how do the particles of a gas travel

A

in straight-line paths until they collide with another particle or another object

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3
Q

what is pressure

A

force per area

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4
Q

what causes gas pressure

A

billions of rapidly moving particles in a gas simultaneously colliding with an object

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5
Q

what is a vacuum

A

empty space

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6
Q

what is a barometer

A

a device used to measure atmospheric pressure

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7
Q

how does a barometer work

A

there is a mercury column in a tube. the height of the mercury column depends on the pressure exerted by particles in the air colliding with the surface of mercury in the dish

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8
Q

what is the relationship between kinetic energy and kelvin temperature

A

the kelvin temp of a substance is directly proportional to the average kinetic energy of the particles of a substance

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9
Q

what is compressibility

A

a measure of how much the volume of matter decreases under pressure

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10
Q

why are gases easier to compress than liquids or solids

A

because of the space between the particles in a gas

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11
Q

why do airbags work

A

the compression of the gas inside the airbag absorbs the energy of the impact

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12
Q

what are the three factors that affect gas pressure

A

the amount of gas
the volume of gas
the temperature

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13
Q

what is an example of the effect of the amount of gas on pressure

A

if you add more air into a raft, the pressure inside the raft will increase

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14
Q

what is an example of the effect of the volume of gas on pressure

A

when a car piston forces gas into a smaller volume, the pressure increases

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15
Q

what is an example of the effect of the temperature on pressure

A

a hot potato chip bag will bulge at the seams because and increase in temp causes an increase in pressure

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16
Q

how are pressure and volume related

A

inversely proportional

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17
Q

how are temperature and volume related

A

directly proportional

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18
Q

what is so special about -273 degrees C

A

it is the same as 0 K

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19
Q

why do you have to use K when solving gas law problems

A

it is not a direct relationship if temp is expressed in celsius
Kelvin is an absolute temperature scale that starts at 0

20
Q

how are pressure and temperature related

A

directly proportional

21
Q

how do pressure cookers reduce cooking time

A

they increase the pressure of the steam which raises the temperature of it which causes the food to cook faster

22
Q

what is the combined gas law

A

PV/nT = PV/nT

23
Q

what has to be constant throughout the combined gas law

A

units

24
Q

what is the ideal gas law

A

PV = nRT

25
Q

Under what conditions are real gases most likely to differ from ideal gases

A

At low temps and high pressures

25
Q

Under what conditions are real gases most likely to differ from ideal gases

A

At low temps and high pressures

26
Q

How is the total pressure of a gas mixture related to the partial pressures of the component gases

A

In a mixture of gases, the total pressure is the sum of the partial pressures of thegases

27
Q

What does gas pressure depend on

A

The number or particles in a given volume and the average kinetic energy of those particles

28
Q

How does Dalton’s law of partial pressures hold true

A

Each component gas exerts it’s own pressure independent of the pressure exerted by the other gases

29
Q

Does the kind of particle affect gas pressure

A

No, amount of gas and their avg KE does

30
Q

If the temperature of a fixed quantity of gas decreases, and the pressure remains unchanged, what happens to the volume

A

It decreases

31
Q

If the temperature of a fixed quantity and a fixed volume of gas changes, what also changes?

A

Pressure

32
Q

If the volume of a container of gas is reduced, what will happen to the pressure inside the container

A

The pressure will increase

33
Q

What happens to the pressure of a gas inside a rigid container if the temp of the gas decreases?

A

Pressure decreases

34
Q

If a balloon is heated, what happens to the volume of the air in the balloon if pressure is constant

A

It increases

35
Q

What is the combined gas law

A

PV/nT

36
Q

What is diffusion

A

The tendency of molecules to move towards ares of lower concentration until the concentration is uniform throughout

37
Q

What is effusion

A

When gas escapes from a tiny hole in its container

38
Q

What is Graham’s law of effusion

A

The rate of effusion of a gas is inversely proportional to the square root of the gas’s molar mass

39
Q

why did the can crush experiment work

A

the particles were heated up, and when it go put into the cold water, they cooled down so the internal pressure decreased causing the external pressure to crush it

40
Q

Increasing the volume of a given amount of gas at a constant temperature causes the pressure to decrease because why?

A

The molecules are striking a larger area w the same force

41
Q

Why does 19.0 grams of fluorine gas at stp contain the same number of molecules as 1/2 a mole of oxygen at stp

A

Because 19.0 of fluorine is 1/2 a mole of fluorine and 1/2 a mole of anything is always the same amount of molecules

42
Q

In class we put a marshmallow peep into a vacuum chamber & removed some of the air in the chamber. What happened to the marshmallow and why?

A

The marshmallow expanded as we continued taking air out of the chamber. As we removed air from the chamber, this decreased the pressure inside bc n and p are directly proportional. This decreased the external pressure on the peep. The volume of the peep increased in order to decrease it’s internal pressure (since v and p are inversely proportional) so that the external and internal pressures could be balanced.

43
Q

You have two containers, each holding 1 mole of Xenon gas at 15°C. Container A has a volume of 3.0 L and container B has a volume of 1.0 L. How does the average kinetic energy of the xenon atoms compare between the two containers?

A

Same in both containers bc avg kinetic energy if particles is directly proportional to their kelvin temp and they both have the same kelvin temp since they are in the same environment

44
Q

You have two containers, each holding 1 mole of Xenon gas at 15°C. Container A has a volume of 3.0 L and container B has a volume of 1.0 L. Compare the forces with which the xenon atoms collide with the sides of each container

A

Same force bc the temp is the same, so their kinetic energies are the same, and they both have the same amount of molecules, so they are moving with the same speed/force

45
Q

You have two containers, each holding 1 mole of Xenon gas at 15°C. Container A has a volume of 3.0 L and container B has a volume of 1.0 L. Compare the pressures of the 2 xenon samples

A

Pressure in container A is less than that of container b bc CA has a bigger volume CB, and when n and t are constant, pressure and volume are inversely proportional