Answer to Question #313504 in Inorganic Chemistry for m12

Question

1.Calculate the Molarity of a solution that contains 20.0 g NaCl in 0.30 L of solution.

2.Calculate the mass in grams of lithium nitrite of 120. mL of 0.500 M solution.

Describe how to prepare the solution.

3 Write the molecular, ionic and net ionic equations for the reactions in 26 and 27 between the following. If

there is no net ionic equation, write “no net ionic equation”:

potassium carbonate and sodium nitrate

Which of the following 1.00 m solutions has the highest boiling temperature?

a) Na2S

b) LiNO3

c) (NH4)3PO4

d) sucrose

Of the following solutions, ................ has the highest freezing temperature and

.................... has the lowest freezing temperature? Your answer should include two

letters in the correct order.

a) 5.0 m KCl

b) 3.0 m LiNO3

c) 2.0 m (NH4)3PO4

d) sucrose

30 .......................The freezing point depression constant, Kf of H2O = 1.86 oC/ m-1

The boiling point elevation constant, Kb of H2O = 0.52 oC oC/ m

Calculate the boiling temperature of a solution of 2.00 m AlCl3

Answer 1

1) M = n(solute)/V(solution) = m(solute)/(Mr(solute)*V(solution)) = 20.0 g /(58.44 g/mol * 0.30 L) = 1.14 mol/L

2) M = n(solute)/V(solution) = m(solute)/(Mr(solute)*V(solution))

0.500 mol/L = m(LiNO₂)/(52.95 g/mol * 0.120 L)

m(LiNO₂) = 52.95 g/mol * 0.120 L * 0.500 mol/L = 3.18 g

3) K₂CO₃ + 2NaNO₃ = Na₂CO₃ + 2KNO₃

2K⁺ + CO₃^2- + 2Na⁺ + 2NO₃^- = 2Na⁺ + CO₃^2- + 2K⁺+ 2NO₃^-

No net ionic equation

4) ΔT_b = K_b*m*i

K_b = molal boiling point constant (0.52 °C/m for aqueous solutions)

m = 1.00 m

Na₂S = 2Na⁺ + S^2-; i = 2+1 = 3

LiNO₃ = Li⁺ + NO₃^-; i = 1+1 = 2

(NH₄)₃PO₄ = 3NH₄⁺ + PO₄^3-; i = 3+1 = 4

For sucrose i = 1

(NH₄)₃PO₄ has the highest boiling temperature

5) ΔT_f = K_f*m*i

K_f = molal freezing point constant (1.86 °C/m for aqueous solutions)

a) KCl = K⁺ + Cl^-; i = 1+1 = 2

ΔT_f = 1.86 °C/m * 5.0 m * 2 = 18.6°C

b) LiNO₃ = Li⁺ + NO₃^-; i = 1+1 = 2

ΔT_f = 1.86 °C/m * 3.0 m * 2 = 11.16°C

c) (NH₄)₃PO₄ = 3NH₄⁺ + PO₄^3-; i = 3+1 = 4

ΔT_f = 1.86 °C/m * 2.0 m * 4 = 14.88°C

d) For sucrose i = 1

Of the following solutions, d) sucrose has the highest freezing temperature and

a) KCl has the lowest freezing temperature?

6) ΔT_b = K_b*m*i

K_b = molal boiling point constant (0.52 °C/m for aqueous solutions)

m = 2.00 m

AlCl₃ = Al³⁺ + 3Cl^-; i = 1+3 = 4

ΔT_b = 0.52 °C/m * 2.00 m * 4 = 4.16°C

T_b = 100°C + 4.16°C = 104.16°C