Practice Problems: Molarity, Normality and Percent Solutions; Laboratory Math

1. What is the Normality  of a 3.6 M Sulfuric acid solution given the molecular weights?( H=1, S=32, O-16)

    a. 1.8 N          b. 3.6N        c. 4.9 N              d. 7.2 N        e. NIL

2. How many grams of HCL is used to prepare 250 ml of a 4.8 solution of HCL? (H-1, Cl-35.5)

    a. 36  G          b. 36.5 g       c. 40 g             d. 43.8 g           e. NIL

3. What is the Molarity of a 2 .5 N solution of NaOH?

a.       1.50 mol/l                   c. 3.35  mol/l                e. NIL

b.      2.5 mol/l                      d. 4.5  mol/l

4. The molecular weight of  H3 PO4 is:

a. 48                            c. 98                            e. NIL

b. 58.5                         d. 98.1

5. How many grams of  NaCl are required to make 1,000 ml. of  0.3 M  solution?

a. 36.3                                     c. 26.32                       e. NIL

b. 52.6                         d. 53

6. What is the Molar concentration of a 20 grm. Of NaOH diluted to 1 liter of distilled water?

a. 1 M                                                              c. 0.5 M                       e. NIL

b. 2 M                                                              d. 1.5 M

 7. What is the amount of CaCl2.H2O in grams is needed  to prepare 0.4 N solution of

Ca Cl2?

a. 8.8                                                              c. 16                            e. NIL

b. 4                                                                  d. 32

  8. One milligram is equal to:

a. 0.001 grm.                                                   c. 0.01 grm.                 e. NIL

b. 0.0001 grm.                                                 d. 0.1 grm.

 9. A 10 mgs. % solution contains:

a.       10 mgs of solute/100ml of solution

b.      10 mgs of solute/100 ml of diluent 

c.       10 mgs of solute/1000 ml of diluent

d.      10 mgs of solute/1000ml of solution

e.       NIL

10. A 2 % solution of 10mg/100ml is diluted 1:100. What is the final concentration?

a. 2 %                                                              c. 0.2 %                       e. NIL

b. 0.02 %                                                         d. 0.002 %

HERE ARE THE ANSWERS

Answers to Quality Control and Quality Assurance Exam and Review Questions

1.        Quality control charts are useful in demonstrating:

a. mean values                                                             d. proper methods

b. accuracy                                                                  e. coefficient of variation

c.    analytical trend

2.        When a range is set by taking the mean value plus minus two standard deviations, the percentage of values of the normal population EXCLUDED from the acceptable range is:

a. 13.6 %                                                                     d. 2.5 %

b. 5 %                                                                         e. NIL

c. 15.9 %

3.        The following may be used to analyze quality control data, EXCEPT:

a. Levey-Jennings plot                                                d. Westgard Rules

b. Shewhart Plot                                                         e.  NIL

c. trends and shifts

4.        The extent to which measurements agree to the true value of the quantity being measured is known as:

a. acceptable limits                                                      c.  precision        e. NIL

b. accuracy                                                                 d.  reliability                           

5.        The reproducibility of test measurements is referred to as:

a. accuracy                                                                  c. quality control  e. NIL

b. precision                                                                 d. reliability

6.        The middle value of a set of numbers that are arranged according to their magnitude is known as:

a. arithmetic mean                                                       c. median           e. NIL

b. geometric mean                                                       d. mode

7.        In a Gaussian distribution, the +- 2 SD range includes the following percentage values:

a. 31.6 %                                                                     c. 12.7 %           e. NIL

b. 68.3 %                                                                     d. 95.7%

8.  Calculate the coefficient of variation when +- 1SD = +-7 mg/dL and the mean is 89 mg/dL:

            a. 6.4 %                                                                       c. 12.7 %         e. NIL

            b. 7.9 %                                                                       d. 15.7 %

9.      When establishing a reference range, it is most desirable to obtain  specimens from at least the following number of individuals:

a. 25                                                                            c. 75                e. NIL

b. 50                                                                            d. 100

10.  Which of the following should be taken into consideration when establishing a reference range?

a. age                                                                           d.  both a & b

b. sex                                                                           e. NIL

c.    Sampling time

                                   

11.  When data fluctuation are due to chance and results are seen to vary in either direction, the problem is referred to as:

a.       experimental error                                     e. NIL

b.      random error

c.       systematic error

d.      all of the above                                                                

12.  The process that encompasses all aspects of laboratory operation including patient ID, specimen collection, assaying and recording is:

a. quality assurance                                       c. quality control         e. NIL

b. reliability                                                     d. internal control

13.  The following  Westgard Rules indicate a random error:

a.   1 (2S), 1 (3S), R (4S)

b.    10 X , 2 (2S), 1(3S)

c.    2 (2S), 1 (2S), 1 (3S)

d.    R (4S), 2 (2S), 2 (1S)

e.    NIL

14.  What assistance does an external quality assurance program provide for the laboratory?

a.       Means to correlate test performed by different departments within the same laboratory.

b.      Evaluation of its performance by comparison with other laboratories using the same method

c.       Data checks with previous tests on the same patient

d.      Limits for reference intervals

e.       NIL

15.  A  sudden shift in daily values in a Q.C chart is likely to be the result  of:

a.      Changing  an operating technologist

b.      Replacing the instruments sample aspiration probe

c.       Changing the spectrophotometer lamp In the middle of the sample run

d.      Running new standards concurrently  with the current standard  lot

e.       NIL

16.  Which of these are classified as random errors?

1.      Mislabeling of sample

2.      Improper mixture of sample and reagent

3.      Sample instability

4.      Deterioration of reagent

A.    1 and 2           B. 3 and 4        C. 1,2 and 3    D. all  of the above     E. NIL

Reference: Fundamentals of Clinical Chemistry by Donald F. Calbreath

Quality Control and Quality Assurance Review Questions

1.        Quality control charts are useful in demonstrating:

a. mean values                                                             d. proper methods

b. accuracy                                                                  e. coefficient of variation

c.    analytical trend

2.        When a range is set by taking the mean value plus minus two standard deviations, the percentage of values of the normal population EXCLUDED from the acceptable range is:

a. 13.6 %                                                                     d. 2.5 %

b. 5 %                                                                          e. NIL

c. 15.9 %

3.        The following may be used to analyze quality control data, EXCEPT:

a. Levey-Jennings plot                                                d. Westgard Rules

b. Shewhart Plot                                                         e.  NIL

c. trends and shifts

4.        The extent to which measurements agree to the true value of the quantity being measured is known as:

a. acceptable limits                                                      c.  precision        e. NIL

b. accuracy                                                                  d.  reliability                           

5.        The reproducibility of test measurements is referred to as:

a. accuracy                                                                  c. quality control  e. NIL

b. precision                                                                  d. reliability

6.        The middle value of a set of numbers that are arranged according to their magnitude is known as:

a. arithmetic mean                                                       c. median           e. NIL

b. geometric mean                                                       d. mode

7.        In a Gaussian distribution, the +- 2 SD range includes the following percentage values:

a. 31.6 %                                                                     c. 12.7 %           e. NIL

b. 68.3 %                                                                     d. 95.7%

8.  Calculate the coefficient of variation when +- 1SD = +-7 mg/dL and the mean is 89 mg/dL:

            a. 6.4 %                                                                       c. 12.7 %         e. NIL

            b. 7.9 %                                                                       d. 15.7 %

9.      When establishing a reference range, it is most desirable to obtain  specimens from at least the following number of individuals:

a. 25                                                                            c. 75                e. NIL

b. 50                                                                            d. 100

10.  Which of the following should be taken into consideration when establishing a reference range?

a. age                                                                           d.  both a & b

b. sex                                                                           e. NIL

c.    Sampling time

                                   

11.  When data fluctuation are due to chance and results are seen to vary in either direction, the problem is referred to as:

a.       experimental error                                     e. NIL

b.      random error

c.       systematic error

d.      all of the above                                                                

12.  The process that encompasses all aspects of laboratory operation including patient ID, specimen collection, assaying and recording is:

a. quality assurance                                         c. quality control         e. NIL

b. reliability                                                     d. internal control

13.  The following  Westgard Rules indicate a random error:

a.    1 (2S), 1 (3S), R (4S)

b.    10 X , 2 (2S), 1(3S)

c.    2 (2S), 1 (2S), 1 (3S)

d.    R (4S), 2 (2S), 2 (1S)

e.    NIL

14.  What assistance does an external quality assurance program provide for the laboratory?

a.       Means to correlate test performed by different departments within the same laboratory.

b.      Evaluation of its performance by comparison with other laboratories using the same method

c.       Data checks with previous tests on the same patient

d.      Limits for reference intervals

e.       NIL

15.  A  sudden shift in daily values in a Q.C chart is likely to be the result  of:

a.       Changing  an operating technologist

b.      Replacing the instruments sample aspiration probe

c.       Changing the spectrophotometer lamp In the middle of the sample run

d.      Running new standards concurrently  with the current standard  lot

e.       NIL

16.  Which of these are classified as random errors?

1.      Mislabeling of sample

2.      Improper mixture of sample and reagent

3.      Sample instability

4.      Deterioration of reagent

A.    1 and 2           B. 3 and 4        C. 1,2 and 3    D. all  of the above     E. NIL

Reference: Fundamentals of Clinical Chemistry by Donald F. Calbreath

Answers to the QA and QC questions are HERE.