**Questions in Laboratory Mathematics**

Laboratory Mathematics is a necessary part of the Clinical Chemistry section of a Clinical Laboratory. Although, reagents and substances now are commercially prepared, it is still crucial that a Medical Technologist or Laboratory Scientist knows how to prepare the most common solutions used in CC. The need for serial dilutions is also essential in any section of the laboratory.

DIRECTIONS: For each of the questions, there is only ONE correct answer. Select the BEST answer.

Questions in Laboratory Mathematics

Determine the molecular weights of the following substances: Atomic weights: H=1, Na=23, Cl=35.5, S=32, O=16, Ca=40, N=14

1. NaCl

2. H2SO4

3. CaCl2.H2O

4. HCl

5. HNO3

Choices: A. 36.5 B. 58.5 C. 63 D. 98 E. 129 F. 111

6. How many milliliters of 0.5 N hydrochloric acid is needed to prepare 250 milliliters of 0.1 N hydrochloric acid?

A. 50 milliliters

B. 200 milliliters

C. 20 milliliters

D. 60 milliliters

E. 25 milliliters

7. If you are to prepare 150 milliliters of normal saline solution, how much of the solute will you need?

A. 1.60 milliliters

B. 10 milliliters

C. 15 milliliters

D. 1.3 milliliters

E. 1.5 milliliters

8. How will you prepare a serum-NSS dilution of 1:25, if you have 0.50 milliliters of serum?

A. Add 0.50 milliliter of serum to 20 milliliters of normal saline solution.

B. Add 0.50 milliliters of serum to 25 milliliters of normal saline solution.

C. Add 0.50 milliliters of serum to 12 milliliters of normal saline solution.

D. Add 0.50 milliliters of serum to 24 milliliters of normal saline solution

E. None of the above

9. What is the weight of CaCl2 needed to prepare 1 liter of 2 Molar solution?

A. 111 grams

B. 55.5 grams

C. 222 grams

D. 200 grams

E. 75 grams

10. What is the Normality of a 0.5% HCl solution?

A. 1.37

B. 1.80

C. 18.25

D. 10.85

E. 0.18

Answers to be posted NEXT WEEK.

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