General Chemistry Answers

Identify what colligative property is applied or observed in the following. Explain

your answer.

1. Salt is mixed with ice in ice cream making.

2. Salt and sugar are used in food preservation.

3. Coolant is added to car radiators.

4. Pressure cooker.

5. Pruned or wrinkled fingers.

Solve for what is being asked.

What is the molar mass of the solute in a solution made by dissolving 34.41

g of an unknown nonelectrolyte compound in 280.0 g benzene. The boiling point of

the solution is 93.2 °C. Benzene has a boiling point of 80.1 °C and molal boiling-

point elevation constant of 2.53 °C/m.

What is the PH of a solution having the following H+ concentration?

a. 5*10^-3 M

b. 0.003M

c. 2.0*10^-6

Identify the Lewis acid in the following reaction.

a) ALCL₃ + CL^- ⤑ ALCL₄^-

b) BF₃ + NH₃ ⤑ BF₃ - NH₃

c) SiCL₄ + 2CL^- ⤑ SiCL₆^-2

d) PF₅ + F^- ⤑PF₆

In each of the reactions listed below, identify the Bronsted-lowery acids?

a. CH₃COOH (aq) + H₂O (l) CH₃COO^-(aq) + H₃0⁺ (aq)

b. HCN (aq) + SO4^-2 ↔ CN^-(aq) + HSO₄^-(aq)

c. HF (aq) + NH₃(g) ↔ F^-(aq) + NH₄⁺(aq)

d. HCIO₄(aq) + N₂H₄(aq) ↔ CIO₄^-(aq) + N₂H₅⁺(aq)

18. In a redox titration, potassium permanganate, KMnO4, was standardized using a 19.60 g/L

FeSO4(NH4)SO4.6H2O, (molar mass = 392.21 g/mol) standard solution. A 20.00 mL of the

standard solution, acidified with H2SO4 was put in a conical flask. A titre volume 15.50

mL of KMnO4 solution was required to reach the end-point. The titration reaction is:

Fe2+(aq) + MnO4

−(aq) → Fe3+(aq) + Mn2+(aq)

(i) Balance the above redox reaction in basic medium.

(ii) Calculate the molarity of the standard solution.

(iii) Determine molarity of MnO4-(aq) in the burette.

1.      Human colour vision is “produced” by the nervous system based on how three different cone receptors interact with photons of light in the eye. These three different types of cones interact with photons of different frequency light, as indicated in the following chart:

Cone Type   Range of Light Frequency Detected

S                          6.00-7.49 x 10¹⁴ s^-1

M                         4.76-6.62 x 10¹⁴ s^-1

L                          4.28-6.00 x 10¹⁴ s^-1

           What wavelength ranges (and corresponding colours) do the three types of cones

detect?

1.      Subshells half-filled with electrons are particularly stable. Can you suggest a possible

physical basis for this claim?

If an average fluorine atom has a mass of 3.16×10-23 g, what is the average mass of a chlorine atom in grams?

A teacher placed a beaker of limonene at the front of a

classroom. At first, the students at the back of the classroom could not smell the limonene. After two minutes,

the smell of limonene had spread throughout the classroom. The air in the classroom was still and calm.

Explain this observation using the particle model of matter.