Basic principles and Practices

. What is the molarity for a solution containing 100 g of NaCl made up to 500 mL with distilled water? Assume a gram molecular weight (from periodic table) of approximately 58 grams. a. 3.45 M b. 1.72 M c. 290 M d. 5.27 M

. What is the normality for a solution containing 100 g of NaCl made up to 500 mL with distilled water? Assume a gram molecular weight (from periodic table) of approximately 58 g. a. 3.45 b. 0.86 c. 1.72 d. 6.9

. What is the percent (w/v) for a solution containing 100 g of NaCl made up to 500 mL with distilled water? a. 20% b. 5% c. 29% d. 58%

What is the dilution factor for a solution containing 100 g of NaCl made up to 500 mL with distilled water? a. 1:5 or 1/5 b. 5 c. 50 or 1/50 d. 10

What is the value in mg/dL for a solution containing 10 mg of CaCl2 made with 100 mL of distilled water? a. 10 b. 100 c. 50 d. Cannot determine without additional information

What is the molarity of a solution containing 10 mg of CaCl2 made with 100 mL of distilled water? Assume a gram molecular weight from the periodic table of approximately 111 g. a. 9 × 10−4 b. 1.1 × 10−3 c. 11.1 d. 90

You must make 1 L of 0.2 M acetic acid (CH3COOH). All you have available is concentrated glacial acetic acid (assay value, 98%; specific gravity, 1.05 g/mL). It will take milliliters of acetic acid to make this solution. Assume a gram molecular weight of 60.05 grams. a. 11.7 b. 1.029 c. 3.42 d. 12.01

What is the hydrogen ion concentration of an acetate buffer having a pH of 3.85? a. 1.41 × 10−4 b. 3.90 × 10−1 c. 0.048 d. 0.15 × 10−6

Using the Henderson-Hasselbalch equation, give the ratio of salt to weak acid for a Veronal buffer with a pH of 8.6 and a pKa of 7.43. a. 14.7/1 b. 1/8.6 c. 1.17/1 d. 1/4.3

The pKa for acetic acid is 4.76. If the concentration of salt is 2 mmol/L and that of acetic acid is 6 mmol/L, what is the expected pH? a. 4.43 b. 6.19 c. 104 d. 56

The hydrogen ion concentration of a solution is 0.000439. What is the pH? a. 3.36 b. 4.39 × 10 −5 c. 4.39 d. 8.03

Perform the following conversions: a. 4 × 10_4 mg = g b. 1.3 × 10_2 mL = dL c. 0.02 mL = μL d. 5 × 10−3 mL = μL e. 5 × 10−2 L = mL f. 4 cm = mm

What volume of 14 N H2SO4 is needed to make 250 mL of 3.2 M H2SO4 solution? Assume a gram molecular weight of 98.08 g. a. 114 mL b. 1.82 mL c. 1.75 mL d. 7 mL

A 24-hour urine has a total volume of 1,200 mL. A 1:200 dilution of the urine specimen gives a creatinine result of 0.8 mg/dL. The serum value is 1.2 mg/dL. What is the final value of creatinine in mg/dL in the undiluted urine sample? a. 160 b. 0.8 c. 960 d. 860

A 24-hour urine has a total volume of 1,200 mL. A 1:200 dilution of the urine specimen gives a creatinine result of 0.8 mg/dL. The serum value is 1.2 mg/dL. What is the result in terms of grams per 24 hours? a. 1.92 b. 0.08 c. 80 d. 19

A new medical technologist was selecting analyte standards to develop a standard curve for a high- performance liquid chromatography (HPLC) procedure. This analyte must have a 100% purity level and must be suitable for HPLC. Which of the following labels would be most appropriate for this procedure? a. ACS with no impurities listed b. USP c. NF d. CP e. ACS with impurities listed

When selecting quality control reagents for measuring an analyte in urine, the medical technologist should select: a. A quality control reagent prepared in a urine matrix. b. A quality control reagent prepared in a serum matrix. c. A quality control reagent prepared in deionized water. d. The matrix does not matter; any quality control reagent as long as the analyte of measure is chemically pure

A patient’s serum sample was placed on the chemistry analyzer and the output indicated “out of range” for the measurement of creatine kinase (CK) enzyme. A dilution of the patient serum was required. Which of the following should be used to prepare a dilution of patient serum? a. Deionized water b. Tap water c. Another patient’s serum with confirmed, low levels of CK d. Type III water e. Type I water

True or False? Laboratory liquid-in-glass thermometers should be calibrated against an NIST-certified thermometer.

Which of the following containers is calibrated to hold only one exact volume of liquid? a. Volumetric flask b. Erlenmeyer flask c. Griffin beaker d. Graduated cylinder

Which of the following does NOT require calibration in the clinical laboratory? a. Electronic balance b. Liquid-in-glass thermometer c. Centrifuge d. Volumetric flask e. Air-displacement pipette

Which of the following errors is NOT considered a preanalytical error? a. During a phlebotomy procedure, the patient is opening and clenching his fist multiple times. b. The blood was not permitted to clot and spun in a centrifuge after 6minutes of collection c. The patient was improperly identified leading to a mislabeled blood sample. d. The serum sample was diluted with tap water. e. During phlebotomy, the EDTA tube was collected prior to the red clot tube.