Chemistry Answers

II. The percentages of aqueous sugar solutions with different concentrations which are separated by a semipermeable membrane are given below. For each of the solutions below, indicate the direction of the flow of water in osmosis.

2% sugar

  5% sugar

  20%  sugar

  9% sugar

  1% sugar

  7% sugar

  5% sugar

  20% sugar

The vehicle that was transporting the dynamite sticks in Part A has been struck by another vehicle. A small fire appears to be spreading from a tire on a vehicle at the scene of the accident. Identify the explosive material that could be involved, and describe the chemical interaction that could be occurring as a result of the collision between the two vehicles. What immediate action should the EHS and FS responders take to protect human health and the environment?

I.

                                   3NaOH(aq) + 3FeCl₃                          NaCl (aq) + 3Fe(OH)₃ (s)

1. What mass of 3Fe(OH)₃ would be produced if 250 mL of 0.250M NaOH were added to a solution containing excess FeCl₃?

2. What volume of 2M NaOH will react with 4.0 g of FeCl₃?

3. What is the concentration of 20.50 mL of NaOH if this was neutralized with 20.0 mL of 0.150 M HCl in the reaction:

NaOH + HCl                       NaCl + HOH

D. A solution of propylene glycol (antifreeze) in the car’s radiator has a freezing point of -20°C. What is the molality of the solution?

E. The boiling point of an aqueous solution is 102.5°C. What is the freezing point of the solution?

Calculate the boiling point and freezing point of the following solutions:

1. 0. 575 molal aqueous solution

2. 1o g of C₆ H₁₂ O₆ dissolved in 259 g water

3. 0.5 mole Br₂ dissolved in 507 g chloroform

At a certain temperature, the 𝐾

p

 for the decomposition of H

2

S

 is 0.709.

H

2

S(g)↽−

−⇀

H

2

(g)+S(g)

Initially, only H

2

S

 is present at a pressure of 0.159 atm

 in a closed container. What is the total pressure in the container at equilibrium?

At equilibrium, the concentrations in this system were found to be[N

2

]=[O

2

]=0.200 M

and[NO]=0.500 M.

N

2

(g)+O

2

(g)↽−

−⇀

2NO(g)

If more NO

 is added, bringing its concentration to 0.800 M,

 what will the final concentration of NO

 be after equilibrium is re‑established?

what mass in grams are in 5.32*10^22 molecules of co2

Suppose we have a sample of ammonia gas (NH3) with a volume of 7.0 mL at a pressure

of 1.68 atm. The gas is compressed to a volume of 2.7 mL at a constant temperature. Use

the ideal gas law to calculate the final pressure.

1. Which solution has the lowest pH?

A. 0.10 M HClO4

B. 0.10 M HClO

C. 0.10 M KOH

D. 0.10 M CH3NH2

2. Which solution has the highest pH?

A. 0.05 M Sr(OH)2

B. 0.10 M Sr(OH)2

C. 0.10 M NaOH

D. 0.15 M NaOH

3. What is the pH of 0.03 M acid solution? The Ka of the acid is 510-3?

A. 1.5

B. 1.9

C. 2.0

D. 2.3 

4. What is the pH of 0.10 M Ba(OH)2 solution?

A. 0.70

B. 1.00

C. 13.00

D. 13.30 

5. What is the [OH- ] of a solution with pH = 4.33?

A. 2.1104 M

B. 2.110-10 M

C. 4.7109 M

D. 4.710-5 M

6. A 0.025 M solution of compound X has pH = 2.15. Which of the following statements is true?

A. Compound X is a strong acid.

B. Compound X is a strong base.

C. Compound X is a weak acid.

D. Compound X is a weak base.

7. A base has % ionization of 0.3%. What is the pH of 0.05 M solution of the base?

A. 1.3

B. 3.8

C. 10.2

D. 12.7

8. What is the K_a of the acid if the pH of its 0.075 M solution is 2.12?

A. 1.0 x 10^-1

B. 1.1 x 10^-1

C. 7.8 x 10^-4

D. 8.5 x 10^-4