G10 Q4L1_Properties of Gases

Question 1

a model used to describe the behavior of gases

Answer 1

Kinetic Molecular Theory of Gases

Question 2

explains how macroscopic properties, such as pressure and temperature, are related to the behavior of molecules

Answer 2

Kinetic Molecular Theory of Gases

Question 3

Kinetic Molecular Theory of Gases is derived from

Answer 3

kinetic molecular theory of matter

Question 4

based on the motion of their atoms

Question 5

Assumptions of the Kinetic Molecular Theory of Gases

Answer 5

Gases are composed of molecules that move in constant random motion.
Gas molecules have no definite volume, but they have a definite mass.
Each molecules moves in a straight line until it collides with another molecule or the walls of the container.
Collision between the molecules is elastic.
There is no attractive force among molecules, between molecules and the wall of the container.
Average kinetic energy of the gas molecules depends only on the temperature of the gas.

Question 6

Gas molecules are not visible to the human eye but the effects of their movements can be detected.

For example, the dust particles move randomly in a beam of light.

Question 7

Gas molecules are very small and very far apart from one another. This causes them to take the _ of their container.

Answer 7

shape

Question 8

Each molecule moves in a straight line until it collides with another molecule or the walls of the container.

Answer 8

Brownian motion

Question 9

Elastic collision means no kinetic energy is

_ when the molecules collide.

Answer 9

lost

Question 10

Elastic collision means no kinetic energy is lost when the molecules collide.

For example, when a gas molecule with an initial kinetic energy collides with another gas molecule, all of the kinetic energy will be transferred.

Question 11

The molecules of gases have _ to _ intermolecular forces of attraction.

This can be seen by the fact that gases expand to achieve the shape of the container or compressed to smaller volumes.

Answer 11

minimal to negligible

Question 12

The higher the temperature, the more energy is acquired by the gas molecules allowing them to move _.

Answer 12

faster

Question 13

a gas that follows all the assumptions of the kinetic molecular theory

Answer 13

ideal gas

Question 14

has molecules that occupy space and interact with one another

Answer 14

real gas

Question 15

Unlike ideal gases, real gases cannot be compressed _.

Answer 15

indefinitely

Question 16

At _ _, the gas molecules are far apart that the attractive force between them is negligible. Real gases behave as ideally.

Answer 16

low pressures

Question 17

At _ _, the gas molecules have higher average kinetic energy. They move faster and expand. As a result, they are far apart from one another, making the attractive force between them negligible. At high temperatures, real gases behave ideally.

Answer 17

high temperatures

Question 18

At low pressures, the gas molecules are far apart that the attractive force between them is negligible. Real gases behave as _.

Answer 18

ideally

Question 19

At high temperatures, the gas molecules have higher average kinetic energy. They move faster and expand. As a result, they are far apart from one another, making the attractive force between them negligible. At high temperatures, real gases behave _.

Answer 19

ideally

Question 20

Gases made up of smaller molecules are more _ than larger molecules.

Answer 20

compressible

Question 21

Helium and other gases with small molecules can behave like ideal gases in _ containers where propane can no longer behave as such.

Answer 21

smaller

Question 22

In smaller containers of a certain volume, larger molecules may no longer behave like ideal gas but smaller molecules still can.

Question 23

At low pressure and high temperature, a real gas behaves like an _ gas. At high pressure and low temperature, attractive intermolecular forces are no longer negligible, and thus the ideal-gas model no longer applies.

Answer 23

ideal

Question 24

formula of Kinetic Emergy

Answer 24

KE=1/2mv^2
KE is in Joules
mass in kilograms
velocity in meters per second

Question 25

average of all the kinetic energies of the gas molecules

Answer 25

Average Kinetic Energy

Question 26

formula of average kinetic energy

Answer 26

3k|b|T/2
T=Temperature of the gas in Kelvin
kb=Boltzmann constant=1.38064852 x 10^-23 J/K

Question 27

The absolute temperature of the gas is _ related to the kinetic energy which is _ related to the velocity of the gas.

Answer 27

directly

directly

Question 28

This means increasing the temperature of the gas results in an increase in velocity.

Question 29

This causes the gas to expand and occupy a greater volume.

Question 30

defined as force applied per unit area

Answer 30

Pressure

Question 31

pressure formula

Answer 31

P is the pressure in Newtons per square meter
F is the force exerted on a surface in Newtons
A is the area of the surface on which the force is applied in square meters.

Question 32

The unit newtons per square meter is also referred to as

Answer 32

Pascals/Pa

Question 33

It is also expressed in terms of psi, which is equivalent to pounds per square inch.

Question 34

1 bar = _ pascals

Answer 34

101325

Question 35

is initially made from a glass tube around 760 mm long filled with mercury and is closed at one end. When the tube is inverted in a dish full of water, some liquid mercury stays inside the tube

Answer 35

barometer

Question 36

A pressure gauge used in measuring the pressure of gases in containers and a barometer used in measuring the atmospheric pressure.

Question 37

The standard unit for pressure, however, is a bar. One bar is equivalent to 101 325 Pa.

Question 38

Millimeters mercury (mmHg), which is also equivalent to Torr is also a common unit. One torr is equal to 760 mm Hg.

Question 39

The nonstandard unit atmosphere is also commonly used. One atmosphere is equal to _ bar

Answer 39

1.01325

Question 40

Each molecule moves in a straight line until it collides with another molecule or the wall of the container. When gas molecules collide with each other and with the walls of the container, no kinetic energy is lost.

The collisions between these molecules are completely elastic. When gas molecules collide, no kinetic energy is lost.

These assumptions indicate that gas molecules collide with the container walls and all collisions do not involve _ of kinetic energy (for ideal gases).

Answer 40

loss

Question 41

The macroscopic property, ,_, is related to the velocity of the particles, a microscopic behavior. It refers to the number of collisions of the gas molecules with the container walls.

Answer 41

Pressure

Question 42

As the velocity of the gas particles increases, so does the pressure exerted on the container.

Question 43

_ pressure is set at one bar (1 bar).

Answer 43

Standard

Question 44

Together with temperature, the standard temperature and pressure (STP) of an ideal gas is set at _°C and 1 bar.

Answer 44

0

Question 45

amount of space matter occupies

Answer 45

Volume

Question 46

Since gas is a state of matter, it also occupies space.

Question 47

One of the assumptions of the kinetic molecular theory of gases states that ideal gas molecules have very small volume compared with their container.

Hence, ideal gases can be compressed _.

Answer 47

indefinitely

Question 48

In reality, gas molecules have _ volumes, thus cannot be compressed indefinitely.

For example, when you try to push a piston down an empty container, it will not be pushed until the end. When this limit is reached, the gases can no longer behave as an ideal gas since repulsive forces become very strong.

Answer 48

definite

Question 49

At a certain smaller volume, large molecules such as propane will already stop behaving like an ideal gas, but smaller molecules like hydrogen and helium may continue to behave like ideal gas in the same volume.

Question 50

Gases also tend to expand to fill the entire container.

If you move a gaseous substance from a smaller container to a larger container, it will quickly expand to fill the larger container.

Question 51

For nonrigid containers such as balloons, the size of the container is approximately equal to the volume of gas in it.

The balance between internal and external pressures determines the volume of a flexible container.

Question 52

For example, if you can bring a balloon to higher layers of atmosphere or on the Moon, where the pressure is lower, the balloon will increase in size (or pop up if it is not durable enough).

Question 53

Volume is expressed in liters (L). For some instances, prefixes such as milli- and kilo- are used to handle small and large magnitudes, respectively.