Clinical Chemistry Reviewer

Saturday, December 14, 2013

7.___________________________________________________Its aim is to remove the introduced air bubbles before the liquid stream reaches the flow cell of the detector.

8.__________________________________________________Transcribe ACA.

9.__________________________________________________ Which part of the DuPont ACA carries a binary code?

10._________________________________________________Range of volume of sample in centrifugal analyzer.

11.________________________________________________What is the usual length of the tubings in FIA.

Fill in the needed items:

Parameter	SFA	FIA
SAMPLE INSERTION	12.	13.
SAMPLE VOLUME	14.	15
REAGENT CONSUMPTION (INDICATE IF MORE OR LESS)	16.	17.
WASHING CYCLE	18.	19.
NUMBER OF SAMPLES	20.	21.
PRECISION	22.	23.

INDICATE WITH AN ARROW WHETHER THE SUBSTANCE IS INCREASED OR INCREASED OR N (NORMAL)

DISEASE/CONDITION	B1	B2	TB
HDN	24.	25.	26.
PREHEPATIC JAUNDICE	27.	28.	29.
POSTHEPATIC	30.	31.	32.
ROTOR’S	33.	34.	35.

Monday, September 2, 2013

Problem Solving: Normality, Molarity, Percent Solution Problems

PROBLEM SOLVING : Normality, Molarity, Percentages

1. WRITE DOWN FORMULA 1^ST.

2. SHOW COMPUTATIONS.

3. ENCLOSE ANSWERS IN BOXES.

ATOMIC WEIGHTS:

Na = 23 H = 1 S = 32

Cl= 35.5 O = 16

1. If you weigh 10 g NaCl solution and dissolve it in 600 ml of diluent. ( 5 pts. each)

A. What is the Molarity?

M= 10

58.5

0.6 L

ANSWER= M = 0.28 M NaCl

B. What is the Normality?

N= M X v or factor

N= 0.28 X 1

ANSWER N = 0.28 N NaCl

C. What is the percent solution?

% = Weight of solute X 100

Total Volume of solution

% = 10 X 100

600

ANSWER % = 1.67%

2. What is the Molarity of a 2 N H2SO4 solution? ( 5 pts.)

M= N

v (valence or factor)

M= 2

ANSWER M = 1 M H2SO4

3. What is the dilution if you add 0.25 ml of serum to 5.0 ml of diluent? ( 5 pts.)

0.25 mL = 1 part

5.0 mL = 20 parts

1:21

ANSWER Dilution = 1:21

Parts of diluent = 5/0/25

0.25

= 20 parts of diluent

DILUTION FACTOR= parts of solute + parts of diluent

Dilution factor = 1 + 20 = 21

ANSWER Dilution = 1:21

4. How would you prepare 1:6 serum dilution? ( 5 pts.)

THERE ARE VARIOUS WAYS TO PREPARE SERUM DILUTIONS:

THE SIMPLEST WAY IS TO CONSIDER 1 mL of SERUM AS 1 PART.

ANSWERS:

1mL of serum = 1 part

5 mL of NSS = 5 parts

6 parts

Dilution = 1:6

0.25 mL of serum = 1 part

0.25 X 5 = 2.25 mL= 5 parts

6 parts

Dilution = 1:6

5. How would you prepare a 0.85 % NaCl solution? (5 pts.)

W=(%) X Total volume of solution

100

W= 0.85 X 100

100

ANSWER W= 0.85 g NaCl diluted to 100 mL of water in a volumetric flask

6. What is the Normality of a 10% CaCl2 solution?

N= % X 10

EW (MW/v)

N= 10 X 10

111/2

ANSWER N = 1.80 N CaCl2

7. Convert 40 mEq/L of calcium to mg/dL

40 mEq X 1L X 20 mg (40 atomic weight / valence)

L 10 dL 1 mEq

ANSWER= 80 mg/dL

Friday, July 12, 2013

Laboratory Math: Percent Solutions, Normality, Molarity Problems, Answers To Practice Problems

ANSWERS TO PRACTICE PROBLEMS:

1. IF YOU HAVE WEIGHED 90 GRAMS OF NAOH AND DISSOLVED IT 1,500 ML OF WATER, WHAT IS THE;

A. PERCENTAGE

% = Weight in grams X 100

Total Volume in mL

% = 90 x 100

1,500

% = 6 % of NaOH solution

B. MOLARITY

M= W in grams

Liter of solution

M = 90

1.5

M = 1.5 M NaOH

C. NORMALITY

N= Mv

N = 1.5 X 1

N = 1.5 N NaOH

2. HOW MANY GRAMS DO YOU NEED TO PREPARE 2M OF NACL?

W = DM X DV X MW

W = 2 X 1 X 58.5

W = 117 grams of NaCl

How: weigh 117 grams of NaCl and dilute it with DH20 up to the 1 Liter mark in a volumetric flask or measure 500 mL of DH2O into a volumetric flask, weigh 117 grams of NaCl and dissolve. Add DH20 up to 1 liter mark.

3. HOW WOULD YOU PREPARE 1N OF HCL?

C1V1 = C2V2

C1= 12 N (Concentrated HCl)

C2 = 1N

V2 = 100 mL (assumption when no volume is given)

V1 = unknown

V1 = C2V2

V1 = 8.33 mL

How: Add 8.33 mL of concentrated HCl to 91.67 mL of DH2O.

4. HOW WOULD YOU PREPARE 0.85% NACL SOLUTION?

W = % X TV (total volume)

100

W = 0.85 X 100 (if no volumes are given assume that TV is 100)

100

W = 0.85 g (grams) of NaCl

How: Measure 50 mL of DH2O into a volumetric flask. Weigh 0.85 grams of NaCl and dissolve completely. Add DH2O up to the 100 mL mark.

5. WHAT IS THE NORMALITY OF A 0.5 M CACL2 SOLUTION?

N = M X v (factor)

N = 0.5 X 2

N = 1 N CaCl2

6. HOW DO YOU PREPARE A 1:10 SERUM DILUTION?

When no volume is given assume that 1 mL is one part; hence,

1 mL = 1 part of solute

9 mL = 9 parts of diluent

10 parts (total)

Hence: dilution is 1:10

How: Add 1 mL of serum to 9 mL of NSS to come up with a 1:10 serum dilution.

7. MAKE UP 500 ML OF 5M SOLUTION OF HCL

C1V1 = C2V2

V1 = C2V2

Before you substitute be sure that all your units are the same. It does not matter what units you used as long as they are similar units. i.e. if you use liters for volume all volumes should be expressed in liters.

V1 = 5 M X 500 mL

12 (12 is standard Normal concentration of concentrated HCl, since valence is 1, N=M.)

V1 = 208.33 mL

How: Add 208.33 mL to 291.67 of DH2O to produce 500 mL of 5M HCl solution.

8. PREPARE THE FOLLOWING WORKING STANDARD SOLUTIONS FROM A STOCK SOLUTION OF 20 MG/DL: STATE VOLUME OF DILUENT AND DILUTION.

A. 15 MG/DL

C1V1 = C2V2

V1 = C2V2

V1 = 15 mg/Dl X 100 mL

20 mg/dL

V1 = 75 mL

75 mL of 20 mg/dL stock solution added to 25 mL of DH2O

B. 10 MG/DL

C1V1 = C2V2

V1 = C2V2

V1 = 10 mg/Dl X 100 mL

20 mg/dL

V1 = 50 mL of 20 mg/dL stock solution added to 50 mL of DH2O

C. 5 MG/DL

C1V1 = C2V2

V1 = C2V2

V1 = 5 mg/Dl X 100 mL

20 mg/dL

V1 = 25 mL of 20 mg/dL stock solution added to 75 mL of DH2O

D. 2 MG/DL

C1V1 = C2V2

V1 = C2V2

V1 = 2 mg/Dl X 100 mL

20 mg/dL

V1 = 10 mL of 20 mg/dL stock solution added to 90 mL of DH2O

Volume of stock solution, diluent and dilution are the following:

Volume of stock solution	Volume of Diluent (DH2O)	Dilution
75 mL	25 mL	1:4 (diluent to solute)
50 mL	50 mL	1:2
25 mL	75 mL	1:4
10 mL	90 mL	1:9