Exam 1 Formulas

Question 1

What is the formula for boiling point elevation?

Answer 1

ΔT_b = ik_bm

temp change = (van’t Hoff)(constant)(molality)

Question 2

What is the formula for freezing point depression?

Answer 2

ΔT_f = ik_fm

temp change = (van’t Hoff)(constant)(molality)

Question 3

What is the formula for molarity?

Answer 3

molarity = (moles of solute)/(liters of solution)

Question 4

What is the formula for mole fraction?

Answer 4

mole fraction of A = (moles of A)/(total moles)

Question 5

What is the formula for molecular weight?

Answer 5

molecular weight = (mass of substance)/(moles of substance)

Question 6

What is the formula for %concentration?

Answer 6

%conc = (mass of solute)/(mass solution) x 100%

Question 7

What is the formula for enthalpy of solution?

Answer 7

ΔH_solution = ΔH_lattice + ΔH_{hydration/solvation}

Question 8

What is the formula for vapor pressure lowering? (Raoult’s Law)

Answer 8

P_solution = x_solvent * Pº

vapor pressure of solution = solvent mole fraction * vapor pressure of pure solvent

Question 9

What is the formula for molality?

Answer 9

molality = (moles of solute)/(kg of solvent)

Question 10

What is the formula for heat?

Answer 10

q = mC_sΔT = mΔH_transition

heat = (moles)(specific heat)(temp change) = (moles)(enthalpy change)

Question 11

What is the formula for the Clasius-Clapeyron Equation which relates vapor pressure and temperature?

Answer 11

ln(P₂/P₁) = (ΔH_vap/R)(1/T₁ - 1/T₂)

P= vapor pressure

ΔH_vap = enthalpy of vaporization

R= gas constant

T = temperature

Question 12

What is the formula for osmotic pressure?

Answer 12

Π = iMRT

osmotic pressure = (van’t Hoff)(molarity)(gas constant)(temp)

Question 13

What is Henry’s Law, the formula for solubility of a gas?

Answer 13

C_gas = k_HP_gas

C = concentration of the gas

k = Henry’s Law constant

P = partial pressure of gas