Dilution Lab Problems and Solutions (Answers)

Dilution Lab Problems and Solutions (Answers)

In the laboratory, you are often asked to prepare dilutions of solutions. These dilution lab problems can sometimes leave you grasping for solutions. Well, fret no more, in this post, simple dilution problems are given with the corresponding answers below. I hope you enjoy this learning process.

Instructions:

For the following problems, identify the given and the unknown. State what formula could be used, and show your computations.

1.    How do you prepare a 1:4 dilution of HCl?
2.    What’s the volume of diluent (NSS) needed to prepare a 1:5 serum dilution with a total of 5 mL?
3.    How do you prepare a Normal Saline Solution (NSS)?
4.    What is the resulting dilution for each tube in this serial dilution?

Tube No.    Volume of stock standard solution in mL    Volume of diluent in mL    Resulting Dilution
1           
2           
3           

5.    How much volume do you need to prepare a 5 ml of a 1:10 dilution?


ANSWERS

1.    How do you prepare a 1:4 dilution of HCl?

A 1:4 dilution indicates that there for every 1 part of the solute, there are 3 parts of the solvent. 4 indicate the total of the parts of the solute and the solvent. The solute is HCl (hydrochloric acid) and the solvent would be distilled water.

The easiest method is to assume that I part = 1 mL (milliliter), hence, 1 part is = 1mL HCl

If 1 part = 1 mL
Hence:
3 parts = 3 mL

When you add the parts, the total is 4, hence, the dilution 1:4

So, to prepare 1:4 dilution, you add 1 mL of HCL to 3 mL of distilled water.


2.    What’s the volume of diluent (NSS) needed to prepare a 1:5 serum dilution with a total of 5 mL?

NSS or Normal Saline Solution is also 85% saline. This is also very simple to solve, since 5 is the total of the solute and diluent parts, you can assume that 1 part = 1 mL.

So, 4 parts is required to complete the 5 parts.

Since 1 part =1 mL
So, 4 parts = 4 mL

Since the total volume is also 5 mL, then by adding 1 mL of serum + 4 mL of NSS; you, therefore, need 4 mL of NSS to prepare the dilution.

3.    How do you prepare a serum dilution of 1:3, if your available serum is only 0.25 mL?

1:3 – indicates 1 part of serum + 2 parts of diluent

Since the available solute or serum volume is only 0.25 mL, you have to equate this to 1 part of the dilution.

Hence, if 1 part = 0.25 mL

Therefore, 2 parts diluent = 0.25 mL x 2 parts = 0.50 mL

Hence, to prepare a serum dilution of 1:3, you can add:
0.25 mL of serum + 0.50 mL of diluent.

1 part + 2 parts = 3 parts

So, the dilution is 1:3


4.    What is the resulting dilution for each tube in this serial dilution?

Tube No.    Volume of standard solution in mL    Volume of diluent in mL    Resulting Dilution
1    0.5 (pure stock soln.)    1     1:3
2    0.5 from tube #1    1    1:9
3    0.5 from tube #2 (mix and discard 0.5 mL)    1    1:27

5.    How much volume do you need to prepare a 5 ml of a 1:10 dilution of standard solution?
1:10 dilution indicates what?

Yes, it indicates that 1 part of standard stock solution is added to 9 parts of diluent.

You can do the easiest method by adding 1 mL of the standard stock solution plus 9 mL of the diluent.

However, since the total volume is stated, which is 5 mL, you have to determine how many parts would the solution consists of.

You can divide 5 mL by 10, to determine the volume of each part.

Hence, 5/10 = 0.5 mL

So, you can now equate 1 part with 0.5 mL
The 9 parts diluent would therefore be = 9 x 0.5 = 4.5 mL

So, you add 0.5 mL standard stock solution to 4.5 mL diluent to come up with a 5 mL total volume of 1:10 standard dilution.

There you go! It’s relatively easy, if you always remember that the dilution factor (DF) is the total of 1 part of the solute and the designated parts of the solvent.

If I say the DF is 5, I’m also stating that the dilution is 1:5. So, there are 1 part of solute + 4 parts of solvent.  

For 1:9

There is one part of solute + 8 parts of the solvent


Dilution is different from ratio because in ratio the numbers remain the same. You don’t add them. Unlike in dilution, you add the parts of the solute plus parts of the solvent.

If you’re performing serial dilution, remember to multiply the previous dilution of the tube from where you got the solute.

Good luck with your laboratory math during your exams or when you’re working.

Questions for laboratory math in Clinical Chemistry

Questions for laboratory math in Clinical Chemistry

Instructions

•    Read each question carefully before answering
•    Follow the procedures of problem solving
o    Determine the given
o    What is asked? (unknown)
o    Connect the given with the unknown using a formula
•    Atomic weights:
o    Na = 23
o    Cl = 35.5
o    Ca = 40
o    H = 1
o    O = 16
o    S = 32

•    Valences 
o    NaCl = 1
o    H2SO4 = 2
o    CaCl = 2
o    HCl = 1

1.    You have weighed 90 grams of sodium chloride (NaCl) in dissolved it to a total volume of 500 ml in a volumetric flask. Determine the following:
a.    Percent solution
b.    Normality
c.    Molarity

2.    If you were to prepare a total volume of 150 ml of the following stock solutions from a 50 mg/dL standard, how would you do it? Show volume of diluent and stock solution.
a.    40 mg/dL
b.    30 mg/dL
c.    20 m/dL
d.    10 mg/dL
ANSWERS WILL BE PUBLISHED NEXT WEEK.

ANSWERS TO CASE ANALYSIS in Clinical Chemistry

ANSWERS TO CASE ANALYSIS in Clinical Chemistry

Laboratory tests are performed on a 50-year old lean woman during an annual physical check-up. She has no family history of diabetes or any history of elevated glucose levels during pregnancy. Her laboratory results are the following:
FBS = 90 mg/dL
Cholesterol = 140 mg/dL
HDL = 40 mg/dL
TAG = 90 mg/Dl
THE ANSWERS ARE THE CHOICES THAT ARE IN BLACK LETTERS

QUESTIONS:
1.    The probable diagnosis of the patient is:
    a. myocardial infarction
    b. gestational diabetes
    c. hypercholesterolemia
    d. hyperlipoproteinemia    e. NIL – APPARENTLY, THE RESULTS ARE NORMAL

2.    What are the risk factors that would indicate a potential risk of this patient developing diabetes?
    1. increased cholesterol value
    2. increased TAG value
    3. decreased HDL value
    4.  increased LDL value
    5. NIL

    a. 1         b. 1 & 2    c. 1,2 & 3    d. 1, 2, 3 & 4     e. NIL

3.    What would be the proper follow-up tests for this patient?
    a. Repeat FBS and OGTT
    b. Repeat TAG, Chole, HDL    c. Repeat all tests
    d. Repeat all tests and OGTT
    e. NIL
4.    In this specific case, what would be the most significant test for DM?
    a. 2 HPPT
    b. FBS
    c. OGTT
    d. RBS
    e. NIL
5.    Using the Friedewald formula, the LDL value of a patient with the following results is:
TC = 150 mg/dL, TAG = 90 mg/dL, and HDL = 36 mg/dL:a.    96 mg/dL
b.    102.69 mg/dL
c.    375 mg/dL
d.    24 mg/dL
e.    NIL
Friedewald formula: Explanation

The Friedewald formula (FF) is an estimation of LDL-c level. It utilizes the following values:

Total Cholesterol (TC), Triglycerides (TG), and high-density lipoprotein cholesterol (HDL-c)

The FF is:

LDL-c (mg/dL) = TC (mg/dL) − HDL-c (mg/dL) − TG (mg/dL)/5

Example is above:

Substituting the given data, you will get:

LDL-c = (150 - 36) - (90/5)

LDL-c = (150 -36) - 18

LDL-c = 96 mg/dL
6.    The reason why the value of glucose is 10-15% lower in whole blood than serum and plasma is:
    a. Glycolysis is more predominant in plasma
    b. Gluconeogenesis occurs only in serum and plasma    c. Red blood cells consume glucose
    d. Glucose is contained mostly in serum
    e. NIL
7.    The value of 110 traditional units of cholesterol in SI units is:
    a. 1.10 mmol/L
    b. 220 mg/dL
    c. 11.0 mmol/L
    d. 6.105 mmol/L    e. NIL  - 110 mg/dl  = 2.8446 mmol/l
           
   
NOTES:

To convert from mg/dL (Traditional units) to mmol/L (SI units)

For total, HDL, and LDL cholesterol divide mg/dL by 38.67

Example 110 mg/dL to SI units

110 mg/dL/38.67 = 2.8846 mmol/L

For triglycerides divide mg/dL by 88.57

Example 150 mg/dL to SI units

 150 mg/dL/88.57 = 1.69357 mmol/L

To convert from mmol/L to mg/dL

For total, HDL, and LDL cholesterol multiply mmol/L by 38.67

Example 2.0 mmol/L to traditional units (mg/dL)

2.0 mmol/L * 38.67 = 77.34 mg/dL

For triglycerides multiply mmol/L by 88.57

Example 3.2 mmol/L to traditional units (mg/dL)

3.2 mmol/L * 88.57 = 283.424 mg/dL
8.    The normal value of TP in SI units is:
    a. 3.2 – 8.5 g/dL
    b. 3.5 – 6.2 g/L    c. 32 – 85 g/L OTHER BOOKS SAY IT’S 60 – 80 g/L
    d. 3.3 – 5.3 g/dL
    e. NIL
9.    In protein measurements, Nessler’s reagent is:
    a. double iodide of potassium and mercury
    b. double ions of mercury and iodine
    c. mercury, iodine and potassium
    d. bonds between an anion and a cation
    e. NIL
10.    The following are methods for cholesterol determination, except:
    a. Van Handel and Zilversmit
    b. Pearson McGavak
    c. Schoenheimer and Sperry
    d. Sperry and Webs
    e. NIL
11.    The serum proteins are the following, EXCEPT:
    a. albumin
    b. globulin    c. fibrinogen
    d. immunoglobulin    e. NIL

12.    When testing for OGTT, the following precautions should be observed, EXCEPT:
    a. The patient should not be ambulatory
    b. The patient should eat only 150 grams of carbohydrates daily for 3 days prior to the test
    c. The patient should fast for 8-12 hours
    d. Strenuous exercise should be avoided
    e. NIL

CASE ANALYSIS in Clinical Chemistry

CASE ANALYSIS in Clinical Chemistry

Laboratory tests are performed on a 50-year old lean woman during an annual physical check-up. She has no family history of diabetes or any history of elevated glucose levels during pregnancy. Her laboratory results are the following:
FBS = 90 mg/dL
Cholesterol = 140 mg/dL
HDL = 40 mg/dL
TAG = 90 mg/dL

QUESTIONS:
1.    The probable diagnosis of the patient is:
    a. myocardial infarction
    b. gestational diabetes
    c. hypercholesterolemia
    d. hyperlipoproteinemia
    e. NIL

2.    What are the risk factors that would indicate a potential risk of this patient developing diabetes?
    1. increased cholesterol value
    2. increased TAG value
    3. decreased HDL value
    4.  increased LDL value
    5. NIL

    a. 1         b. 1 & 2    c. 1,2 & 3    d. 1, 2, 3 & 4     e. NIL

3.    What would be the proper follow-up tests for this patient?
    a. Repeat FBS and OGTT
    b. Repeat TAG, Chole, HDL
    c. Repeat all tests
    d. Repeat all tests and OGTT
    e. NIL

4.    In this specific case, what would be the most significant test for DM?
    a. 2 HPPT
    b. FBS
    c. OGTT
    d. RBS
    e. NIL

5.    Using the Friedewald formula, the LDL value of a patient with the following results is:
TC = 150 mg/dL, TAG = 90 mg/dL, and HDL = 36 mg/dL:
a.    96 mg/dL
b.    102.69 mg/dL
c.    375 mg/dL
d.    24 mg/dL
e.    NIL

6.    The reason why the value of glucose is 10-15% lower in whole blood than serum and plasma is:
    a. Glycolysis is more predominant in plasma
    b. Gluconeogenesis occurs only in serum and plasma
    c. Red blood cells consume glucose
    d. Glucose is contained mostly in serum
    e. NIL

7.    The value of 110 traditional units of cholesterol in SI units is:
    a. 1.10 mmol/L
    b. 220 mg/dL
    c. 11.0 mmol/L
    d. 6.105 mmol/L
    e. NIL

8.    The normal value of TP in SI units is:
    a. 3.2 – 8.5 g/dL
    b. 3.5 – 6.2 g/L
    c. 32 – 85 g/L
    d. 3.3 – 5.3 g/dL
    e. NIL

9.    In protein measurements, Nessler’s reagent is:
    a. double iodide of potassium and mercury
    b. double ions of mercury and iodine
    c. mercury, iodine and potassium
    d. bonds between an anion and a cation
    e. NIL

10.    The following are methods for cholesterol determination, except:
    a. Van Handel and Zilversmit
    b. Pearson McGavak
    c. Schoenheimer and Sperry
    d. Sperry and Webs
    e. NIL

11.    The serum proteins are the following, EXCEPT:
    a. albumin
    b. globulin
    c. fibrinogen
    d. immunoglobulin
    e. NIL

12.    When testing for OGTT, the following precautions should be observed, EXCEPT:
    a. The patient should not be ambulatory
b. The patient should eat only 150 grams of carbohydrates daily for 3 days prior to the test
    c. The patient should fast for 8-12 hours
    d. Strenuous exercise should be avoided
    e. NIL

ANSWERS CAN BE READ HERE.

Answers to Review Questions On Instrumentation

ANSWERS to REVIEW QUESTIONS ON INSTRUMENTATION

1. d - flame photometry
2. a - quartz
3. c - particles
4. a - molarity
5. c - dilution
6. e - not in the list (you should multiple the dilutions with the original concentration
7. d - all of the above
8. c - obviate the need for matched detectors
9. a- the color of the reagents
10. c - fluorometer
11. c - fluoroscence is directly proportional to temperature
12. b - heparin
13. d - fluoride
14. b - antecubital fossa
15. b - antecubital fossa
16. b - 20 to 22
17. a - Beer Lamvert's Law
18. a - burner assembly
19. c - spectrophotometry
20. a - light given off by excited atoms
21. a - absorbance
22. d - freezing point depression
23. b - fluorescence
24. a - hollow cathode lamp
25. c - charged particles
26. e - read out errors of cuvette and sprectro
27. a - didymium and lithium
28. a - aspirator, atomizer, flame
29. d-volumetric flask
30. b - solid and liquid preparations
31. d - liters
32. e - not in the list (NIL)
33. a - negative to positive
34. b - the inviolvement of solvent and solute
35. e - not in the list
36. b - the substance to be measured should be hydrated

Review Questions on Instrumentation and Venipuncture for Clinical Chemistry

1. Particulate formation is a problem in analysis of:
a. ultraviolet  spectrophotometry            d. flame photometry
b. fluorescence                    e. NIL
c. atomic absorption

2. For photometric measurements below 320 mu, the cuvette must be:
a. quartz                        d. NaCl
b. tungsten glass                    e. Pyrex glass
c. borosilicate glass

3. Nephelometry is used to measure:
a.    ultraviolet absorbing material
b.    infrared absorbing material
c.    particles
d.    colored solutions
e.    NIL

4. The gram-molecular weight per liter of solution is:
a.  Molarity                    c.  Normality        e. NIL
b.  Molality                    d.  Percent

5.  It involves the preparation of a weaker solution from a stronger solution:
a.  serial dilution                c.  dilution        e. NIL
b.  percent                    d.  gravimetry

6. To solve for the dilution of a solution, you have to:
a.  multiply all the number of parts of the diluent with the original concentration
b.  add the number of parts of the solute and the solvent
c.  add all the numerators and denominators
d.  add all the volumes and multiply by the original concentration
e. NIL

7. Which of the following formula correctly describes the relationship between absorbance  and % T ?
a. A= 2- log % T                    c. A= - log T
b. A = log 1/T                        d. all of the above
                            e. NIL

8. A chopper is used in a dual beam spectrophotometer in order to:
a.    reduce the number of moving  parts
b.    facilitate wavelength  scanning
c.    obviate the need for matched detectors
d.    reduce stray light
e.    NIL

9. The reagent blank corrects for absorbance caused by:
a.    the color of reagents
b.    sample turbidity
c.    bilirubin and hemolysis
d.    all of the above
e.    NIL

10. Which instrument  requires a primary and secondary monochromator?
a.    flame photometer
b.    atomic absorption
c.    fluorometer
d.    nephelometer
e.    NIL

11. All of the following statements about fluorometry are true, except:
a.    fluorometry is more sensitive than spectrophotometry
b.    both excitation and emission spectra are characteristics  of the analyte
c.    fluorescence  is directly proportional to temperature
d.    unsaturated  cyclic molecules are often fluorescent
e.    NIL

12. The ideal anticoagulant because of its natural presence in the blood:
a. citrate                        c. oxalate        e. NIL
b. heparin                        d. fluoride

13. The anticoagulant of choice for glucose because it serves as preservative :
Select from the above choices

14. The most common site of venipuncture:
a. wrist veins                        c. ankle veins        e. NIL
b. antecubital fossa                    d. cubital  veins

15. The following are sites of arterial puncture, except:
a. radial                        c. brachial        e. NIL
b. antecubital  fossa                    d. femoral

16. The ideal gauge of needle for venipuncture is:
a. 22- 25                        c. 21-23        e. NIL
b. 20-22                        d. 18-20

17. It is the law applied to spectrophotometry:
a.  Beer-Lambert’s Law            c.  Kirchoff’s Law
b.  Newton’s Law                d.  Absorptivity Coeffecient
                                e. NIL

18. The following are basic components of the  spectrophotometer, except;
        a.  burner assembly                c.  cuvette               e. NIL
        b.  monochomator                d.  exit slit

19.    The more light absorbed, the higher  the concentration of analyte in this technique of measuring the amount of light absorbed  by a solution:
a.    atomic absorption                d. fluorometry      
b.    nephelometry                e. NIL
c.    spectrophotometry                    

20. The basis of EFP  is the measurement of:
a.    light given off by excited atoms
b.    light absorbed at wavelength of resonance line by dissociated atoms
c.    energy emitted by ultraviolet treated atoms
d.    energy emitted by infrared treated atoms
e.    NIL

21. 2- log T is a definition of (T= transmission):
    a. absorbance                d. electron density        e. NIL
     b. ionic strength                e. electrophoretic density

22.In Osmometry, concentration of substance can be measured by:
   a. colorimetry                d. freezing point depression
    b. appropriate filters            e. NIL
    c. ionized atoms

23.Quenching is a problem in analysis of:
   a. ultraviolet  spectrophotometry        d. flame photometry
   b. fluorescence                e. NIL
   c. atomic absorption

24. For AAS measurements the light source is usually the:
a. hollow cathode lamp                d. Tungsten light bulb
b. Deuterium lamp                    e. NIL
c. halogen lamp

25.Electrophoresis is used to measure :
a.    ultraviolet substances                e. NIL
b.    infrared absorbing materials
c.    charged particles
d.    colored solutions

26.The water blank corrects for absorbance caused by:
a.    the color of reagents                 e. NIL
b.    sample turbidity
c.    bilirubin and hemolysis
d.    all of the above

27. The internal standards in EFP, are:
a.    Didymium and lithium
b.    Cesium and lithium
c.    Potassium and didymium
d.    Cesium and didymium
e.    NIL

28.    The parts of the burner assembly are the following:
a.    Aspirator, atomizer, flame
b.    Aspirator, ionizer, flame
c.    Atomizer, emitter, flame
d.    Atomizer, ionizer, flame
e.    NIL

29.    The most accurate vessel in volumetric measurements is the:
a.    Erlenmeyer flask
b.    Graduated cylinder
c.    Serological pipette
d.    Volumetric flask
e.    NIL

30.    Volumetric measurements are generally used in:
a.    Liquid preparations only
b.    Solid and liquid preparations
c.    Solid preparations only
d.    AIL
e.    NIL

31.    The unit of volume in volumetric measurements is:
a.    Deciliter
b.    Micriolter
c.    Milliliter
d.    Liter
e.    NIL

32.    In electrophoresis, the basis of separation are the following, EXCEPT:
a.    Charges of ions
b.    Electrophoretic media
c.    Net charge of particles
d.    Concentration of ions
e.    NIL

33.    The movement of ions in electrophoresis is from:
a.    Negative to positive
b.    Positive to negative
c.    Negative to negative
d.    Positive to positive
e.    NIL

34.    The principle of chromatography is:
a.    The movement of charged particles in an electric field
b.    The involvement the solute and solvent
c.    The measurement of emitted light
d.    The excitation of ions in solution
e.    NIL

35.    Chromatography is affected by the following factors, EXCEPT:
a.    Density of particles in solution
b.    Size of particle
c.    Affinity of particles to chromatographic media
d.    pH
e.    NIL

36.    The following precautions are observed in Gravimetry, EXCEPT:
a.    The balance should be adjusted to zero
b.    The substance to be measured should be hydrated
c.    The substance should be uncontaminated
d.    The vessels used should be clean and dry
e.    NIL

CLICK HERE FOR THE CORRECT ANSWERS

Review Questions on Laboratory Mathematics Clinical Chemistry

1. For you to be able to interpret a quality control chart, you must have these number of data:
    A. 20 control values                C. 20 standard values
    B. 10 control values                 D.10 standard values
                             E. NIL

2. 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

3. .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

4. 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

5. The molecular weight of  H3 PO4 is:
a. 48            c. 98            e. NIL
b. 58.5            d. 98.1

6. 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

7. 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

8. 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

9. One milligram is equal to:
a. 0.001 grm.                    c. 0.01 grm.        e. NIL
b. 0.0001 grm.                    d. 0.1 grm.

10. 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

11. 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 %


ANSWERS WILL BE GIVEN NEXT WEEK.

ASPARTATE AMINOTRANSFERASE DETERMINATION Review Questions and Answers

1.    State the principle of the test.

AST in the serum catalyzes the transfer of an amino acid group to a keto acid group to form oxaloacetate and L-glutamate. This is measured spectrophotometrically at 505-535 nanometers.

2.    Name sources of error in this method.

Hemolyzed serum will increase values 10-15 X
Turbid, lipemic and icteric serum needs serum blanking for accuracy
Altered temperatures could either increase nor decrease values
Prolonged or shortened incubation time at specified conditions could increase or decrease values respectively

3.    What is the purpose of allowing the reagents to come to room temperature.

The purpose is to allow the reagents to inactivate the reagents so that they could react properly.

4.    Differentiate AST from ALT. Cite specific differences.

CRITERIA                     AST                                                      ALT
Substrate    L-aspartate & alpha-ketoglutarate            L-alanine & alpha-ketoglutarate
Old name    SGOT                                                       SGPT
One of the end products    oxaloacetate                       Pyruvate
Amount in inside serum    10-15 times                        5-8 times
Major clinical significance    heart                                Liver
       

5.    What is the component of the SGOT substrate?

L- aspartate and alpha-ketoglutarate

Answers to Normality and Molarity Review Questions

Solving the Normality and Molarity of solutions is quite easy by remembering the relationship of Normality to Molarity.

1.    Normality may be equal but is always greater than the Molarity in the same solution.

2.    If the valence is 1, Normality is equal to Molarity.

Try solving these problems. Atomic weights: Na = 23; Cl = 35.5, H = 1, Ca = 40, Valences: Ca = 2, NaCl = 1, HCl = 1.

1.    If you have dissolved 20 grams of sodium chloride in 1.5 Liter of distilled water, what is the:
1.1.    Normality

You have to remember that Normality is the Gram Equivalent Weight of substances. Hence, valence is involved. The formula would be:

N = W/GEW/Liter of solution
GEW = W/MW/valence

So, you have to solve first the MW (sum of atomic weights);
MW = 23 (Na) + 35.5 (Cl) = 58.5

Thus, substituting the values: GEW = 20/58.5/1

GEW = 0.3418803

N = GEW/Liter of solution
N = 0.3418803/1.5
N = 0.2279202

Where:
N - Normality
W = weight of substance
GEW = Gram Equivalent Weight
MW = Molecular Weight
M = Molarity

1.2.    Molarity

Since you already know the Normality of the solution, you can make use of the short-cut formula, which is:

M = N/valence

Thus, substituting the values:

M = 0.2279202  x 1
M = 0.2279202

The answer is the same. This follows the rule: If the valence is 1, Normality is equivalent to Molarity.

1.3.    Percent solution

You don’t usually need the molecular weights when solving percent solutions. You could use the general formula:      

% = weight/total volume x 100

NOTE:

In solving for percent solutions, you have to convert the volume to milliliters. So,

1.5 Liters x 1000 mL/1 Liter = 1, 500 mL

Hence:
% = 20/1,500 x 100
% = 1.33333%

2.    What is the Molarity of 1 N Hydrochloric acid?
 
Again in this problem, since you know the Normality, make use of the short-cut formula:
      Thus:

    M = N/valence
    M = 1/1
    M = 1

Again: If the valence is 1, Normality is equivalent to Molarity.       

3.    What is the Normality of 0.8 M calcium chloride?

Use the short-cut formula:
N = M x valence
N = 0.8 x 2
N = 1.6

ALANINE AMINOTRANSFERASE (ALT) DETERMINATION Questions and Answers

1.    Discuss the principle of the method.

ALT in the serum catalyzes the transfer of an amino acid group to a keto acid group to form pyruvate and L-glutamate. This is measured spectrophotometrically at 505-535 nanometers.

2.    Aside from sodium hydroxide, what reagent could also be used to alkalinize the solution?

Potassium hydroxide

3.    Why should the distilled water used in dissolving your NaOH pellets be CO2 free?

Because carbon dioxide can affect the transfer of the amino group to the keto acid group due to its carbon content.  The carbon atom may act as an acceptor molecule in the reaction. This would falsely decrease your values.

4.    Why do we use a semi-log graphing paper in plotting your calibration curve?

Because the it is simpler to use since the graphing paper will find the logarithms of the values beforehand.

How to Solve Normality and Molarity of Solutions

Solving the Normality and Molarity of solutions is quite easy by remembering the relationship of Normality to Molarity.

1.    Normality may be equal but is always greater than the Molarity in the same solution.

2.    If the valence is 1, Normality is equal  to Molarity.

Try solving these problems. Atomic weights: Na = 23; Cl = 35.5, H = 1, Ca = 40, Valences: Ca = 2, NaCl = 1, HCl = 1.

1.    If you have dissolved 20 grams of sodium chloride in 1.5 Liter of distilled water, what is the:

1.1.    Normality
1.2.    Molarity
1.3.    Percent solution

2.    What is the Molarity of 1 N Hydrochloric acid?

3.    What is the Normality of 0.8 M calcium chloride?

CLICK HERE FOR THE ANSWERS.

CLINICAL CHEMISTRY 2 DIAGNOSTIC QUIZ

MATCHING TYPE: 

MATCH COLUMN B WITH COLUMN A

COLUMN A (SUBSTANCE) 

1. GLUCOSE 
2. CHOLESTEROL 
3. TAG 
4. BUA
5. CREATININE 
6. BUN 
7. HDL 
8. TB H.
9. B1 
10. B2 

COLUMN B (CONVERSION FACTOR TO S.I.) 

A. 0.357
B. 0.113
C. 0.01128
D. 0.0258
E. 0.059
F. 0.0555
G. 0.1357
H..88.4
I. 0.555
J. 0.0359
K. 17.1


ESSAY:

1. DISCUSS THE PREPARATION OF ALKALINE PICRATE.