Chapter 13 in class lecture:

Question 1

What is the equation for molality?
What is molality used for?
what is the symbol for molality

Answer 1

moles of solute/ kg of solution

2. ) volume tends to change with temp, and molality is useful for colligative properties
3. ) m

Question 2

how to solve for mol fraction?
what is the abbreviation of a mol fraction?
when is a mol fraction most commonly used?

Answer 2

• mols of desired component of mixture/ total # of mols in the mixture.
• (x)
• to find partial pressures of gases.

Question 3

How to solve for mass %?

Answer 3

(mass of desired component/ total mass of solid) * 100%

Question 4

What is PPM?

What is the equation for PPM?

Answer 4

Parts per million

(mass of desired component/ total mass of solid) x 10 ^6

Question 5

What is PPB?

What is the equation for PPB?

Answer 5

Parts per billion

(mass of desired component/ total mass of solid) x 10 ^9

Question 6

What is true of the solubility of solids?

Answer 6

solubility increases as temperature

Question 7

What is true of the solubility of gases?

Answer 7

solubility of gas in a solution is proportional to the pressure of the gas above the solution

Question 8

What is Henry’s Law?

Answer 8

solubility of a gas in a solution is equal to: K x P
K= proportionality constant
P= proportionality constant (specific to any given gas)

Question 9

What are colligative properties?

Answer 9

properties that depend only on the amount of of stuff dissolved in the solution, not on the identity of the stuff.

Question 10

What are the colligative properties?

Answer 10

1. ) vapor pressure lowering/depression
2. ) Freezing point depression
3. ) Boiling elevation
4. ) Osmotic pressure

Question 11

What equation do you use for vapor pressure lowering?

Answer 11

Raoult’s law: P(solution)= P(solvent) * xXsolvent

Question 12

Partial Pressure?

Answer 12

{Pressure(substance * mols(substance)} +{Pressure(substance * mols(substance)} + {Pressure(substance * mols(substance)}

Question 13

What happens to vapor pressure as you add more stuff to the solution?

Answer 13

It lowers

Question 14

What is the Van’t Hoff factor of a covalent bond if it isn’t stated in the problem?

Answer 14

1

Question 15

What is the Van’t Hoff factor of a ionic bond if it isn’t stated in the problem?

Answer 15

• the amount of individual atoms or polyatomic ions the substance breaks down into
• Ex: NaCl = I = 2

Question 16

Describe the process of determining the vapor pressure using the Van’t Hoff Factor:

Answer 16

• 1st you need to get the necessary componets of the problem: mols solute and solvent, Van’t hoff factor, and the pressure of the solute @ T.
• 2nd: mols solute/mols solv + mols solu X I
• 3rd: take this number and multiply it by the P(solu) @ T.

Question 17

What is the Equation for Bp elevation:

Answer 17

DeltaT(b) = K(b) x m x i
Change in boiling point
Boiling point elevation
molality
Van't Hoff Factor

Question 18

What is the equation for Fp Decline:

Answer 18

DeltaT(f) = -K(f) * m * i
change in freezing point
Freezing point depression constant

Question 19

What is the equation for Osmosis/Osmotic pressure?

Answer 19

Pi = M * R * T * i
(osmotic pressure)
Molarity
Gas constant 
Temperature
Van't Hoff factor

Question 20

What does it mean to be spontaneous

Answer 20

requires no energy to complete