Ch.5 Phases and phase changes

Question 1

Which phase is said to have a fixed shape and volume, and particles do not flow past each other?

Answer 1

Solid

Question 2

What are the two types of solids?

Answer 2

Amorphous - not ordered, strong material

Crystalline - Ordered structure, contains a repeating pattern. (there are 4 types of crystalline solids)

Question 3

What are the crystalline solids?

Answer 3

Ionic solids
Molecular - molecules that are not ionic
Covalent network - molecules that contain covalent bonds
Metallic - contains delocalized electrons

Question 4

Which phase is said to have no fixed shape but does have a fixed volume?

Answer 4

Liquids

Question 5

The resistance of a liquid to flow is known as

Answer 5

Viscosity

Question 6

What is surface tension?

Answer 6

amount of energy needed to increase the surface area of a liquid

Question 7

The attraction of molecules between 2 different substances is known as?

Answer 7

Adhesive force

Question 8

What is capillary action?

Answer 8

Movement of a liquid up the side of a narrow tube, against gravity

Question 9

Which phase is said to have no fixed shape or any volume?

Answer 9

Gas

Question 10

The generic formula of pressure is?

Answer 10

force/area

Question 11

A standard unit of gas is?

Answer 11

Paschal (N/meter squared)

Question 12

Which phase transition is fusion?

Answer 12

A solid goes to a liquid form (melting)

Question 13

Which phase transition is Freezing?

Answer 13

liquid to a solid

Question 14

Which phase transition is VAporization?

Answer 14

liquid to a gas

Question 15

Which phase transition is condensation?

Answer 15

gas to a liquid

Question 16

Which phase transition is sublimation

Answer 16

Solid to a gas

Question 17

Which phase transition is Deposition

Answer 17

gas to a solid

Question 18

Which form of energy determines if phases change?

Answer 18

Thermodynamics (ΔG)

Question 19

To go from a solid to a liquid, how would this affect ΔG

Answer 19

Heat is required to melt something, this would mean the ΔH would be positive (Endothermic) and ΔS would be positive as this is a favorable reaction.
The overall ΔG would be positive and form a spontaneous reaction.

Question 20

What is the Enthalpy of fusion (ΔHf)?

Answer 20

how much heat is needed to melt 1 mol of substance.
The unit is given in kJ/mol (Q=mΔHf)
Where is the mass of water/substance

Question 21

What is Heat of vaporization (ΔHvap)?

Answer 21

The heat required to vaporize 1 mol of substance.

Question 22

The phase of a substance depends on what two factors?

Answer 22

Temp and pressure

Question 23

What is the difference between triple point and critical point?

Answer 23

The triple point is where all 3 passes are at equilibrium

critical point is the terminal point of liquid gas

Question 24

What is supercritical fluid?

Answer 24

A substance that has qualities of both gas (low viscosity) and liquid (higher density)

Question 25

The average kinetic energy of a gas is proportional to?

Answer 25

temperature of the gas

Question 26

What is the ideal gas behavior?

Answer 26

High temp make substances more gas-like Lots of volume and little pressure make favorable behavior

Question 27

When dealing with gas, what should the unit for temp be?

Answer 27

Kelivin | C + 273

Question 28

What is boyle's law?

Answer 28

Pressure and volume are inversely related. | p1 V1 = p2 V2

Question 29

What is Charles's law?

Answer 29

Volume and temp of a gas are directly related | V1/T1 = V2/T2) & (V1/T1 = K

Question 30

What is Avagadro's LAw?

Answer 30

Volume of gas is directly related to the number of mol of gas particle (V1/n1 = V2/n2) & (V/n = K)

Question 31

What are the standard molar volume units for gas?

Answer 31

STP = 1 atm and 0°C (273K) | 1 mole = 22.4L

Question 32

What is the formula for the IDeal gas law?

Answer 32

``` PV = nRT R = Ideal gas constant R = 0.08L atm/mol K R = 8.31 J/mol K ```

Question 33

How do real gases compare to ideal?

Answer 33

``` Real gas particles do have size may exhibit molecular forces (Interforces) Real gas equations use the Vander Waals equation (P + a/Vm squared) (Vm - b) = RT V-b = volume taken up by gas P + a/Vm - Vm - molar volume a - attractive intermolecular forces b - size of particles ```

Question 34

In regard to the Vander Waals equation, a polar molecule will exhibit a

Answer 34

larger "A" term, and behave less ideal-like (compared to non-polar)

Question 35

What is Dalton's law?

Answer 35

The total pressure of the mixture of gasses equas the sum of the partial pressures of individual gasses. The pressure from a gas is independent of other gasses but depends solely on the total pressure and mole fraction of said gas.

Question 36

How do you calculate mole fraction?

Answer 36

Xgas = ngas/ntotal | xgas = Pgas/Ptotal

Question 37

What is Graham's Law?

Answer 37

Smaller lighter particles diffuse faster than larger ones

Question 38

Movement of particles can be described as what type of energy?

Answer 38

Kinetic

Question 39

What is the KE equation?

Answer 39

KE = 1/2mV squared

Question 40

What is a solution?

Answer 40

homogeneous mixture

Question 41

(T/F) solutions can exist in any phase.

Answer 41

True

Question 42

(T/F) Solutions can only be formed from one phase.

Answer 42

False. | Can be formed from components of different phases

Question 43

What is Dissolution?

Answer 43

When a solute interacts with a solvent (disolve).

Question 44

What is the difference between a solute and a solvent?

Answer 44

A solute is the minority part. It is typically solid. | A solvent is the majority component and breaks particles into ions.

Question 45

With respect to solutions, what does the term like dissolves like mean?

Answer 45

Polar solutes dissolve in polar solvents | non-polar in non-polar

Question 46

When does precipitation occur in a solution?

Answer 46

After saturation has reached the maximum

Question 47

What are the units to describe saturation?

Answer 47

g/L

Question 48

What two factors affect solubility?

Answer 48

Temp and pressure

Question 49

Gas is more soluble in liquids at which temp? Why?

Answer 49

lower temp. | Due to the kinetic energy, high temp = high KE for gas

Question 50

Which molecules are always soluble?

Answer 50

alkali earth metals | and Nitrate, Chlorate, Acetate

Question 51

Which molecules are sometimes soluble?

Answer 51

Halides unless within Ag, Pb, Hg Sulfate unless with Ca, Sr, Ba, Pb

Question 52

Which molecules are always insoluble?

Answer 52

CO3^2- PO4^3- S^-2 SO3^2-

Question 53

Which molecules are sometimes insoluble?

Answer 53

Hydroxides and metal oxides - unless present with Ca, Sr, Ba

Question 54

Concentration is measured in what 3 ways?

Answer 54

Molarity Molality Normality

Question 55

What is Molarity?

Answer 55

Molarity (M) - equals moles of solute/liter of solution (mol/L)

Question 56

What is molality?

Answer 56

molality (m) - moles of solute/kilogram of solvent (mol/kg) | - In low concentrations of solute volume isn't effected much so 1kg = 1L

Question 57

What is Normality (N)?

Answer 57

equivalents/liter of solution | -used in acid/base reactions

Question 58

How do you calculate normality?

Answer 58

N(acid) = molarity of acid x acidic protons per molecule N(base) = Mbase (mol/L) x hydroxide ions per molecule

Question 59

What is the solubility equilibrium?

Answer 59

Ksp = Products/reactants | solids and liquids not included

Question 60

What would a high Ksp value mean?

Answer 60

high solubility

Question 61

What would a low Ksp value mean?

Answer 61

Insoluble

Question 62

How do you calculate molar solubility?

Answer 62

Ksp = [cation][Anion]

Question 63

What is the common Ion effect?

Answer 63

The solubility of an ionic species decreases when one of its component ions is already present in a solution