CWEA - LAB ANALYST III with Correct Answers 2024/2025

CWEA - LAB ANALYST III with Correct Answers 2024 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 -EnterobacterThe 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