Question

1. Find the molality of the solution and boiling temperature prepared from a 15% (by mass) solution of KCl. Kb= 0.512

2. Given the following set of data for the initial rates of the reaction 3A+2B (Arrow) Products (answer is NOT 0.33)

Determine the Rate Law

[A]      [B]                           Rate

0.30    0.40                       5.088E-3

0.60    0.40                       6.410E-3

0.90   0.80                        1.47E-3

3. Given the Reaction: NH3(aq)+ HCL (aq) (arrow) NH4CL , Consider the following changes and determine the change or shift

a)add HCL

b) add NAOH

c) Remove NH4CL

d) Raise temperature

4. List the steps you would take to determine the freezing constant (Kf) for benzopheone. Without going into much detail

5. List the steps involved in finding Hrxn of HCL+NAOH (arrow) NaCl + H2O

IF YOU COULD SOLVE EACH ONE, AND WRITE OUT EACH STEP YOU DID LEGIBLY. THANK YOU, read the questions carefully. Number 3 again the answer is NOT 0.33 I already solved it, and need help.

Answer 1

Ans 1

Basis 100 of solution (KCl + water)

Mass of KCl = 15 kg = 15 kg x 1000g/kg = 15000 g

Moles of KCl = mass/molecular weight

= (15000 g) / (74.55 g/mol)

= 201.21 mol

Mass of water = 85 kg

Molality = moles of KCl / mass of water

= 201.21/85

m = 2.37

Boiling point elevation

KCl = K+ + Cl- (i = 2)

Ts - Tb = i x Kb x m

Ts = boiling point of solution

Tb = boiling point of water

i = van't Hoff factor = 2

m = Molality = 2.37

Ts - 100 = 2 x 0.512 x 2.37

Ts = 102.42 °C