gases

Question 1

What are the three normal phases of matter?

Answer 1

Solids, liquids, gases

Question 2

How can phases of matter be defined?

Answer 2

According to their macroscopic physical properties and microscopic atomic and molecular properties

Question 3

What term is used to refer collectively to individual atoms and molecules?

Answer 3

Particle

Question 4

What is a condensed phase?

Answer 4

A phase that is difficult to compress

Question 5

What characterizes a fluid phase?

Answer 5

A fluid phase flows easily

Question 6

What two key properties relate to particle separation and motion?

phases

Answer 6

Condensed phase and fluid phase

Question 7

What happens to a phase with large particle separation?

Answer 7

It can be easily compressed

Question 8

What allows a phase with translation motion to behave?

Answer 8

It can flow

Question 9

What are the types of motion that particles can have?

Answer 9

Translational, rotational, vibrational

Question 10

Which type of motion is present in an atomic gas?

Answer 10

Only translational motion

Question 11

How can we detect different motions in materials?

Answer 11

Spectroscopy

Question 12

What is the significance of quantized energy levels in spectroscopy?

Answer 12

Only photons with energies matching the gaps can be absorbed or emitted

Question 13

What does heat capacity measure?

Answer 13

The amount of heat needed to raise the temperature

Question 14

What does an increase in heat capacity indicate?

Answer 14

More types of motion are present

Question 15

What structural characteristic defines ordered materials?

Answer 15

A regular, repeating structure

Question 16

What are crystalline solids known for?

Answer 16

They have an ordered structure

Question 17

What types of states can solids exist in?

Answer 17

Ordered and disordered states

Question 18

What are ordered solids called?

Answer 18

Crystals

Question 19

What are disordered solids called?

Answer 19

Amorphous or glasses

Question 20

What are ordered liquids with certain shapes called?

Answer 20

Liquid crystals

Question 21

What is the most important method to detect order in materials?

Answer 21

Diffraction

Question 22

What happens to X-rays passed through an ordered material?

Answer 22

They are diffracted at a precise angle defined by the repeating structure

Question 23

What optical property do many crystalline materials exhibit?

Answer 23

Birefringence

Question 24

What influences the strength of particle interactions?

Answer 24

Separation and chemical nature

Question 25

What keeps forces between particles in gases small to negligible?

Answer 25

Large separation between particles

Question 26

What types of attractive interactions occur in liquids and solids?

Answer 26

Electrostatic, van der Waals, hydrogen bonding

Question 27

What are electrostatic forces?

Answer 27

Forces that exist between charged atoms or molecules

Question 28

What happens when like charges are present?

Answer 28

They are repulsed

Question 29

What occurs when unlike charges are present?

Answer 29

They are attracted

Question 30

What can induce a dipole in a neighboring molecule?

Answer 30

The dipole on one molecule

Question 31

What defines a hydrogen bond?

Answer 31

An interaction between a hydrogen atom and an electronegative atom in another molecule

Question 32

What are the characteristics of hydrogen bonds?

Answer 32

They can be strong and are directional

Question 33

What happens to particles when they are too close to one another?

Answer 33

Repulsive forces will push them apart

Question 34

What forces dominates typical interactions between particles at small and larger separations?

Answer 34

Repulsive forces dominate at small separations, attractive forces at larger separations

Question 36

What are the two assumptions that define an ideal gas?

Answer 36

1. No interparticle forces 2. Particles have zero volume ## Footnote These assumptions are generally untrue but are acceptable for gases with low density.

Question 37

What happens to the forces and volumes of particles in a gas with sufficiently low density?

Answer 37

They are negligible. ## Footnote This allows the ideal gas assumptions to hold true under certain conditions.

Question 38

What does Boyle’s Law state about pressure and volume?

Answer 38

p ∝ 1/V ## Footnote This law was formulated in 1662.

Question 39

What does Charles’s Law state about volume and temperature?

Answer 39

V ∝ T ## Footnote This law was formulated in 1787.

Question 40

What does Avogadro’s Law state about volume and the number of moles?

Answer 40

V ∝ n ## Footnote This law was formulated in 1811.

Question 41

What is the equation of state for an ideal gas?

Answer 41

p V = n R T ## Footnote This equation relates pressure, volume, number of moles, and temperature.

Question 42

How is the pressure of a mixture of gases calculated?

Answer 42

It is equal to the sum of the partial pressures of each gas. ## Footnote This allows for the calculation of total pressure in gas mixtures.

Question 43

What are the two types of collisions that can occur in gas particles?

Answer 43

1. Elastic collisions 2. Inelastic collisions ## Footnote Each type has different characteristics regarding kinetic energy.

Question 44

What is conserved during elastic collisions?

Answer 44

Total kinetic energy. ## Footnote In elastic collisions, there is no loss of kinetic energy.

Question 45

What occurs in inelastic collisions regarding kinetic energy?

Answer 45

There is a change in total kinetic energy. ## Footnote Inelastic collisions may result in energy being transformed into other forms.

Question 46

What is conserved in both elastic and inelastic collisions?

Answer 46

Momentum. ## Footnote Conservation of momentum applies to all types of collisions.

Question 48

What is an ideal gas?

Answer 48

An ideal gas is a gas that could not be liquefied.

Question 49

Why can an ideal gas not be liquefied?

Answer 49

Because there are no interparticle interactions in an ideal gas.

Question 50

How can a gas be liquefied?

Answer 50

By cooling or by increasing pressure.

Question 51

What happens as the temperature of a gas increases?

Answer 51

The vapour pressure increases until the liquid and gas have the same density.

Question 52

What is the significance of the critical temperature (TC)?

Answer 52

At the critical temperature, the phase boundary disappears and a single phase is present.

Question 53

What do we call the single phase present at the critical temperature?

Answer 53

A supercritical fluid.

Question 54

What is the shape of the distribution of speeds in a maxwell distribution curve?

Answer 54

A single peak and an asymmetric shape.

Question 55

How do temperature and particle mass affect the maxwell distribution curve?

Answer 55

They change the width and height of the distribution but not the shape.

Question 56

What has a greater effect on the kinetic energy distribution: temperature or speeds?

Answer 56

Temperature.

Question 57

What is the relationship between kinetic energy and temperature?

Answer 57

The dependence is linear for kinetic energy.

Question 58

What is the relationship between speed and temperature?

Answer 58

It goes with the square root for speed.

Question 59

What does collision frequency indicate?

Answer 59

The number of collisions an individual particle has during one second.

Question 60

What does collision density measure?

Answer 60

How many collisions occur for all the particles in 1 cubic metre during 1 second.

Question 61

What is the mean free path?

Answer 61

How far, on average, a particle travels between collisions.

Question 62

What happens when a small hole is opened in the wall of a vessel with a vacuum on the other side?

Answer 62

The gas will effuse out of the vessel.