Water Chemistry & Contaminant Identification Flashcards
7 cards from real CWS practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Water Chemistry & Contaminant Identification flashcards as text
Which parameter is used to measure the ability of water to neutralize acids?
Answer: Alkalinity
Alkalinity measures water's capacity to neutralize acids, primarily due to bicarbonate, carbonate, and hydroxide ions.
What is the maximum contaminant level (MCL) for nitrates in drinking water set by the EPA?
Answer: 10 mg/L
The EPA MCL for nitrates in drinking water is 10 mg/L (as nitrogen) to prevent methemoglobinemia in infants.
Trihalomethanes (THMs) in drinking water are primarily formed when:
Answer: Chlorine reacts with natural organic matter
THMs form as disinfection byproducts when chlorine reacts with naturally occurring organic matter in source water.
A water sample has a pH of 5.5. This water would be classified as:
Answer: Slightly acidic
A pH of 5.5 is below the neutral point of 7.0, making the water slightly acidic.
Which dissolved gas is the primary cause of red water complaints related to iron?
Answer: Oxygen
Dissolved oxygen causes ferrous (clear) iron to oxidize into ferric (red/brown) iron, producing red water complaints.
Total Dissolved Solids (TDS) in water is best measured by which method?
Answer: Gravimetric analysis after evaporation
TDS is measured gravimetrically by filtering a sample, evaporating the water, and weighing the remaining residue.
Sodium fluoride is added to drinking water primarily to:
Answer: Prevent dental cavities
Fluoride is added to drinking water at controlled levels (typically 0.7 mg/L) to prevent tooth decay in the population.