Deck 7: Laboratory Mathematics and Solution Preparation

Question 1

Calculate the concentration expressed in percent,if 10 g of NaOH is diluted to 500 mL with water.

A) 1%
B) 2%
C) 5%
D) 10%

Answer 1

2%

Question 2

Report a laboratory result with the most number of significant figures as the accuracy of the final result.

Answer 2

False

Question 3

MATCHING
Match the term with the appropriate definition.
density

A)the amount of matter per unit volume of a substance
B)relates the weight of 1 mL of a solution and the weight of 1 mL of pure water at 4°C (1 g)

Answer 3

the amount of matter per unit volume of a substance

Question 4

The term dilution refers to:

A) the volume or number of parts of the substance to be diluted in the total volume.
B) the volume or number of parts of the substance to be diluted in the parts of the final solution.
C) an expression of concentration that indicates the relative amount of substance in solution.
D) all of the above.

Question 5

Match the following terms with an appropriate definition.
blank solution

A)a solution prepared from a stock solution and usually stored in the refrigerator
B)one that contains a known, exact amount of the substance being measured
C)one that contains reagents used in the procedure but not the substance to be measured

Question 6

A significant figure should contain only the digits in a number needed to express the precision of the measurement.

Question 7

MATCHING
Match the term with the appropriate definition.
specific gravity

A)the amount of matter per unit volume of a substance
B)relates the weight of 1 mL of a solution and the weight of 1 mL of pure water at 4°C (1 g)

Question 8

The more digits that are used in laboratory assay results,the more precise the answer is.

Question 9

Match the following terms with an appropriate definition.
working standard solution

A)a solution prepared from a stock solution and usually stored in the refrigerator
B)one that contains a known, exact amount of the substance being measured
C)one that contains reagents used in the procedure but not the substance to be measured

Question 10

Laboratory results should only contain the digits necessary for the precision of the determination.

Question 11

Match the following terms with an appropriate definition.
standard solution

A)a solution prepared from a stock solution and usually stored in the refrigerator
B)one that contains a known, exact amount of the substance being measured
C)one that contains reagents used in the procedure but not the substance to be measured

Question 12

In rounding off numbers:

A) when the digit next to the last one to be retained is less than 5, the last digit should be left unchanged.
B) when the digit next to the last one to be retained is greater than 5, the last digit is increased by 1.
C) if the additional digit is 5, the last digit reported is changed to the nearest even number.
D) follow all of the above.

Question 13

What is the molarity of a solution containing 50 g of NaCl per liter?

A) 0.2M
B) 0.5M
C) 0.9M
D) 1.5M

Question 14

If a serum specimen is diluted 1:2 with buffer beginning in tube 2 and serially rediluted 1:2 in each of five subsequent test tubes,what is the concentration of serum in tube 5?

A) 0.5
B) 0.25
C) 0.125
D) 0.06