CWEA GRADE 1 LAB ANALYST EXAM ACTUAL EXAM 200 QUESTIONS AND CORRECT DETAILED ANSWERS WITH RATIONALES |AGRADE

CWEA GRADE 1 LAB ANALYST EXAM 2023-2024 ACTUAL

EXAM 200 QUESTIONS AND CORRECT DETAILED ANSWERS

WITH RATIONALES |AGRADE

During acid base titration, titrant is added to the sample with -

ANSWER- Buret

When preparing diluted calibration standards from a stock standard, use

combination of the following to get the most precise standard -

ANSWER- Class A volumetric flask and class A volumetric pipet

At a given temperature, the intensity of the acidic or basic character of a

solution is indicated by - ANSWER- pH or hydrogen ion activity

pH measurement requires the following - ANSWER- voltmeter, glass

pH electrode, reference electrode, and a temperature compensating

device

Conductance measurements are temperature compensated to -

ANSWER- 25 degrees C

Conductivity meter is calibrated with - ANSWER- 0.0100 N potassium

chloride standard

Alkalinity is reported as - ANSWER- Alkalinity mg CaCO3/L

The hardness determination by EDTA titration measures - ANSWERCalcium and magnesium

The indicator for the hardness determination is - ANSWER- eriochrome

Black T

EPA acceptable primary standards for the turbidity determination

include - ANSWER- formazine only

BOD determination is an empirical test in which standardized lab

procedures are used to - ANSWER- determine the relative oxygen

requirements of wastewaters, effluents and polluted waters

Sample pretreatment for BOD - ANSWER- assuring that the samples are

neutralized to pH range between 6.5 and 7.5 and any residual chlorine

has been dechlorinated

Disinfection - ANSWER- Process designed to kill most microorganisms

in wastewater, including all essentially pathogenic bacteria

Fecal coliform bacteria - ANSWER- Bacteria found in feces of warm

blooded animals

Total coliform group - ANSWER- All of the aerobic and faculative

anaerobic, gram negative, nonspore-forming, rod shaped bacteria that

ferment lactose in 24-48 hours at 35 degrees C

Lab test results for an individual environmental sample within an

analytical batch may be rejected when - ANSWER- A known error has

occured

Precision is measured by - ANSWER- Analyzing replicate samples

Accuracy - ANSWER- The combination of bias and precision of an

analytical procedure, which reflects the closeness of a measured value to

a true value

Bias - ANSWER- Consistent deviation of measured values from the true

value, caused by systematic errors in a procedure

Precision - ANSWER- Measures the degree of agreement among

replicate analyses of a sample, usually expressed as the standard

deviation

Random Error - ANSWER- Consistent deviation of measured values

from the true value, caused by systematic errors in a procedure

Total Solids - ANSWER- Well mixed sample is evaporated in a weighed

dish and dried to constant weight in an oven at 103-105 degrees C