7 LABORATORY MATHEMATICS AND SOLUTION PREPARATION

Question 1

How would 6.32 be rounded off to one less decimal place?
a. 6.32
b. 6.4
c. 7.0
d. 6.3

Answer 1

d. 6.3

Question 2

How would 15.57 be rounded off to one less decimal place?
a. 15.6
b. 15.5
c. 16.0
d. 15.0

Answer 2

a. 15.6

Question 3

How would 25.96 be rounded off to one less decimal place?
a. 26.0
b. 25.9
c. 25.6
d. 26.96

Answer 3

a. 26.0

Question 4

The exponent 10^−2 represents:
a. 100
b. 1000
c. 0.1
d. 0.01

Answer 4

d. 0.01

Question 5

A unique characteristic of specific gravity versus density is that specific gravity is:
a. The amount of matter per unit volume of a substance
b. That all substances have this property
c. That it represents size of substance
d. That it is applicable only to solutions

Answer 5

d. That it is applicable only to solutions

Question 6

Molarity is:
a. The amount of one substance relative to the amounts
of other substances in the solution
b. Relative concentrations of the components of a mixture
c. The gram-molecular mass (or weight) of a compound per liter of solution
d. Expression of one amount relative to another amount

Answer 6

c. The gram-molecular mass (or weight) of a compound per liter of solution

Question 7

Dilution is:
a. The amount of one substance relative to the amounts of other substances in the solution
b. Relative concentrations of the components of a mixture
c. The gram-molecular mass (or weight) of a compound per liter of solution
d. Expression of one amount relative to another amount

Answer 7

b. Relative concentrations of the components of a mixture

Question 8

Three grams (3 g) of solute in 100mL of solvent equals _____% (w/v).
a. 0.3
b. 3
c. 30
d. 300

Answer 8

b. 3

Question 9

Twenty grams (20 g) of solute dissolved in 1L of solvent equals _____% (w/v).
a. 0.2
b. 2
c. 20
d. 200

Answer 9

b. 2

Question 10

If 6mL of liquid is placed in a volumetric flask and the volume is brought to 100mL total, the solution is what percent of liquid?
a. 0.6%
b. 6%
c. 60%
d. None of the above

Answer 10

b. 6%

Question 11

How many grams of NaCl would be used to prepare 1000mL of a 5% (w/v) solution of NaCl?
a. 0.5 g
b. 5 g
c. 50 g
d. 500 g

Answer 11

c. 50 g

Question 12

If there is 25 g of NaCl per liter of solution, what is the molarity?
a. 025M
b. 0.43M
c. 0.5M
d. 1.0M

Answer 12

b. 0.43M

Question 13

How many grams of NaCl are needed to prepare 1000mL of a 0.5M solution of NaCl?
a. 5 g
b. 15 g
c. 29 g
d. 58.4 g

Answer 13

c. 29 g

Question 14

How much calcium chloride (CaCl2) is needed to prepare 500mL of a 0.5M solution of CaCl2?
a. 27.7 g
b. 40.0 g
c. 57.8 g
d. 115.6 g

Answer 14

a. 27.7 g

Question 15

What is the correct formula for calculating a percent (w/v) solution?
a. Grams of solute/Volume of solution×100
b. Grams of solute×Volume of solvent×100
c. Volume of solvent/Grams of solute×100
d. Grams of solute×Volume of solvent/100

Answer 15

a. Grams of solute/Volume of solution×100

Question 16

If a solution contains 20 g of solute dissolved in 0.5L of water, what is the percentage of this solution?
a. 2%
b. 4%
c. 6%
d. 8%

Answer 16

b. 4%

Question 17

How is a 25% w/w solution prepared?
a. 0.25 g solute and 75 g solvent
b. 2.5 g solute and 97.5 g solvent
c. 25 g solute and 75 g solvent
d. 75 g solute and 25 g solvent

Answer 17

c. 25 g solute and 75 g solvent

Question 18

How many milliliters (mL) of bleach in an original bottle are needed to prepare a 10% solution?
a. 0.1mL bleach and 100mL water
b. 1.0mL bleach and 90mL water
c. 10mL bleach and 90mL water
d. Bleach is already a 10% solution in the original bottle

Answer 18

c. 10mL bleach and 90mL water

Question 19

What is the dilution factor if 0.5mL of serum is added to 2mL of diluent?
a. 0.5
b. 1.5
c. 2.5
d. 5

Answer 19

d. 5

Question 20

What volume of 25% alcohol is needed to prepare 500mL of 15% alcohol?
a. 30mL
b. 300mL
c. 350mL
d. 375mL

Answer 20

b. 300mL

Question 21

A ratio is:
a. The amount of one substance relative to the amounts of other substances in the solution
b. Relative concentrations of the components of a mixture
c. The gram-molecular mass (or weight) of a compound per liter of solution
d. Expression of one amount relative to another amount

Answer 21

d. Expression of one amount relative to another amount

Question 22

If only 25mL of a 9% saline solution is available in the laboratory, how many mL of 5% saline solution can be prepared using all available saline solution?
a. 4.5mL
b. 25.0mL
c. 45.0mL
d. 100mL

Answer 22

c. 45.0mL

Question 23

Concentration is:
a. The amount of one substance relative to the amounts of other substances in the solution
b. Relative concentrations of the components of a mixture
c. The gram-molecular mass (or weight) of a compound per liter of solution
d. Expression of one amount relative to another amount

Answer 23

a. The amount of one substance relative to the amounts of other substances in the solution

Question 24

To dilute a serum specimen 1:10, _____ parts of serum would be added to _____ parts distilled water.
a. 1, 10
b. 1, 9
c. 0.5, 4.5
d. Both b and c

Answer 24

b. 1, 9

Question 25

If 0.1mL of serum, 5mL of reagent, and 4.9mL of distilled water are mixed together, what is the dilution of the serum in the final solution? a. 1:5 b. 1:10 c. 1:50 d. 1:100

Answer 25

d. 1:100

Question 26

If a glucose standard solution contains 10mg/dL of glucose, a 1:10 dilution of this standard contains how much glucose? a. 0.01mg/dL b. 0.1mg/dL c. 1mg/dL d. None of the above

Answer 26

c. 1mg/dL

Question 27

What is the dilution factor if 4mL of serum is added to 12mL of diluent? a. 3 b. 4 c. 12 d. 15

Answer 27

b. 4

Question 28

Serum is diluted with an equal amount of diluent (such as tube #1, 1:2 and tube #2, 1:2). What is the concentration in tube #2 if the original concentration was 100mg/dL? a. 12.5mg/dL b. 25.0mg/dL c. 50.0mg/dL d. 75.0mg/dL

Answer 28

b. 25.0mg/dL

Question 29

If a total of 125mL of a 10% solution is diluted to 500mL in a 500-mL volumetric flask, what is the concentration of the resulting new solution? a. 0.25% b. 2.5% c. 25% d. None of the above

Answer 29

b. 2.5%

Question 30

You are asked to make a 1:2 dilution using 1.5mL of serum. How much diluent do you need to use? a. 1.5mL b. 3.0mL c. 15mL d. 30mL

Answer 30

a. 1.5mL

Question 31

Which of the following “recipes” gives you a 1:5 dilution? a. 0.25mL serum+4.75mL of diluent b. 2mL of serum+18mL of diluent c. 0.25mL serum+1mL of diluent d. 1.5mL serum+13.5mL of diluent

Answer 31

c. 0.25mL serum+1mL of diluent

Question 32

The dilution created by 1.5 mL serum + 13.5 mL of diluent is: a. 1:20 b. 1:10 c. 1:100 d. 1:1000

Answer 32

b. 1:10

Question 33

If you make a five-tube twofold dilution using 2mL of serum, what is the concentration of serum in tube #4? a. 0.125mL b. 0.25mL c. 1mL d. 2mL

Answer 33

a. 0.125mL