Quiz 3 - Summer 2015 (Page 2 of 3) in pdf

Quiz 3 - Summer 2015 Page 2

9) Below is an enlarged schematic of a hydrometer. The meniscus of the solution is shown on the image. The

specific gravity of the solution being measured is:

a. 0.988

b. 0.990

c. 0.9905

d. 0.992

d. None of the above

10) As the distillation of the ethanol/water solution proceeded during your lab, the specific gravity of the solution

in the 1000mL Erlenmyer flask should have:

increased with time / decreased with time / not have changed with time.

11) As the distillation of the ethanol/water solution proceeded during your lab, the specific gravity of the distillate

samples being collected should have

increased with time / decreased with time / not have changed with time .

Questions 12-14. Use the table below of density (g/mL), temperature, and percentage of ethanol in water to

answer questions 12 - 14.

12) The ethanol/water solution has a density of 0.9300 g/mL at 30°C. The percent alcohol

(reported to two decimal

is ______________ percent.

points)

13-14) You need a solution that is 36.22% ethanol in water at 25°C. The density of this solution

(reported to four

should be ____________.

decimal places)

Question 15. Below are the chromatograms produced when testing a purple marker in different solvents. Study

the figures and answer the True/False question below.

Solvent B

Solvent A

15) True /False The solute-solvent interactions between the blue dye and solvent are stronger in Solvent A.

Quiz 3 - Summer 2015 Page 2