CWEA - Lab Analyst III Exam Questions With Correct Answers

What does COLOR measure? - Answer Amount of color units (CU) in a sample. Color caused by natural metallic ions (Fe & Mg) & industrial wastes. What is the test summary for COLOR? - Answer Sample -> Tubes -> Compare to color standards over light source Which of the following techniques is used to isolate anionic surfactants (as MBAS) from the sample matrix? - Answer Extraction In the cyanide determination, which one of the following is not an interference? - Answer Halogenated aromatics Which of the following is not a major interference in phenol determination? - Answer Hydroxy derivatives of benzene A freshly prepared sodium hydroxide (NaOH) solution is standardized against primary standard potassium acid phthalate (KHC8H4O4). 0.8000 grams of potassium acid phthalate was dissolved into 50 mL CO2-free water. 2-3 drops of phenolphthalein were added. The sample was titrated to a faint pink endpoint with 22 mLs sodium hydroxide. What is the normality of the sodium hydroxide? - Answer 0.178 N What does an ICP source consist of? - Answer A flowing stream of argon gas ionized by an applied radio frequency In gas chromatography, electron capture detectors (ECD) are used to detect which of the following compounds? - Answer Chlorinated hydrocarbon pesticides Why is methlyene chloride replaced by hexane in sample preparation for analyses detected by GC electron capture detection (ECD)? - Answer Chlorine compounds are detected by ECD Which of the following methods is used to determine pesticides? - Answer EPA Method 608 What analysis uses the purge and trap technique? - Answer Volatile organic compound analysis The test for inhibitory residues on glassware and plastic ware determines the toxic or stimulatory effects of dishwashing detergents used for bacterial analysis. Which bacterial genera is used for this test? - Answer Enterobacter The Water Suitability Test (Test for Bacteriological Quality of Reagent Water) determines the toxic or stimulatory effects of the distilled or deionized water system. Which bacteria genera is used for this test? - Answer Enterobacter Short-term toxicity tests are inappropriate for: - Answer determining chronic toxicity. Basic requirements for toxicity tests do not include: - Answer documented re-use of control test organisms. A test in which solutions and test organisms are placed in test chambers and kept there for the duration of the test is called a: - Answer static test. A test in which solution is replaced continuously in test chambers through the test duration is called a: - Answer flow through test. A preliminary test designed to establish approximate toxicity of a solution is called a: - Answer range finding test. A toxicity test designed to establish concentration at which a particular end point occurs is called a: - Answer definitive test. Which of the following types of control samples may be used to determine accuracy? - Answer Certified reference material