General Chemistry Answers

The osmotic pressure of a benzene solution containing 15.0 g of polystyrene per liter was found to be 8.5 torr at 25 °C. What is the average molecular weight, in kg/mol, of the polystyrene in this solution? Round your answer to three (3) significant figures. Omit the unit in your final answer.

Find the osmotic pressure at 25°C when 60.0 mL of a solution containing 5.60 grams of glucose (MW=180 g/mol) is prepared.

a. 12.7 atm

b. 10 atm

c. 11 atm

d. 1.3 atm

Find the mass of nonelectrolyte X (MW =142 g/mol) require to make 250 mL of a solution having an osmotic pressure of 600 mmHg at 25 °C.

a. 12.4 g

b. 10.3 g

c. 1.15 g

d. 115 g

Find the mass of the nonelectrolyte X (MW=142 g/mol) required to make 250 mL of a solution having an osmotic pressure of 600 mmHg at 25°C.

a. 12.4 g

b. 10.3 g

c. 1.15 g

d. 115 g

 Identify the possible intermolecular force attraction in the following: 

a. NaCl ------ H2O

b. NH3 ------ NH3

c. H2S ------- H2S

d. O2 ------- O2

e. HCl ------ HCl

f. CH3OH ------ CH3OH

g. H2 ---------- H2

h. Na2S ------ HCl

i. Br2 ------- Br2

 j. H2O ----- H2O

For the next three items, refer to this BALANCED redox reaction: CH4 + 2 O2 --> CO2 + 2 H2O. Answer the succeeding questions.

How many electrons are lost in the reaction?

A 3.5 L sample at 360C and 5.2 atm contains 0.7 moles

   of a gas. If 0.3 mole of the gas is added to the sample

   without changing the temperature and pressure, what is

   the new volume?

I When placed in water HBr (g) write a balanced equations and what type of solution it is

A solution contains 2P.5 g of cholecalciferol which is also known as Vitamin D3

(C27H44O) in 4500 mL of methanol (CH3OH).

1. Students are asked to develop a plan for separating Al2O3(s) from a mixture of powdered Fe2O3(s) and powdered Al2O3(s) using chemical reactions and laboratory techniques.
2. One student proposes that Al2O3(s) can be separated from the mixture by adding water to the mixture and then filtering. Explain why this approach is not reasonable.
   
3. A second student organizes a plan using a table. The first two steps have already been entered in the table as shown in the upper table above. Complete the plan by listing the additional steps that are needed to recover the Al2O3(s). List the steps in the correct order and refer to the appropriate reaction by number, if applicable.
   
4. The second student recovers 5.5 g of Al2O3(s) from a 10.0 g sample of the mixture. Calculate the percent of Al by mass in the mixture of the two powdered oxides. (The molar mass of Al2O3 is 101.96 g/mol, and the molar mass of Fe2O3 is 159.70 g/mol.)