CIVL 3140 EXAM #1 SPRING, 2018 Part I. MULTIPLE CHOICE 2 PTS EACED CLOSED BOOK!
ID: 286658 • Letter: C
Question
CIVL 3140 EXAM #1 SPRING, 2018 Part I. MULTIPLE CHOICE 2 PTS EACED CLOSED BOOK! CLOSED N 1. True color in surface waters is primarily caused by: a. Dissolved organics b. Dissolved inorganics c. Suspended organics 2. Turbi idity in surface waters is primarily caused by Dissolved and colloidal solids Colloidal and suspended solids Dissolved and suspended solids a. b. c. d. Volatile solids 3. The predominant form of alkalinity in most natural waters is: a. Carbon dioxide b. Carbonate c. Hydroxide d. Bicarbonate 4. Iron dissolves in water primarily under the following conditions: Anaerobic, reducing conditions a. b. Aerobic, reducing conditions c. Anaerobic, oxidizing conditions d. Aerobic, oxidizing conditions 5. Total dissolved solids in water can be estimated by the following parameter: a. Alkalinity +hardness b. Calcium carbonate equivalent of cationic species c. Calcium carbonate equivalent of anionic species d. Conductivity 6· The element in drinking water that may cause mottling of the teeth is: a. Fluoride b. Sulfate c. Chloride d. CalciumExplanation / Answer
1. True color in surface water is primarily caused by a)dissolved organics. Apparent color of water is caused by both dissolved and suspended materials, but true color is measured after removing all suspended materials. Because suspended materials cause scattering of light.
2.Turbidity in surface water is primarily caused by c)dissolved and suspended solids. Due to these materials water appears cloudy or murky. The materials include silt and clay particles, fine organic and inorganic matter and microscopic organisms.
3.The predominant form of alkalinity in most natural waters is d)bicarbonate. Alkalinity is the capacity of water to resist changes in pH for which the water would become more acidic. The most common ion that has acid-neutralizing capacity in natural water is bicarbonate.
4. Iron dissolves in water primarily under d) aerobic,oxidizing conditions. Dissolved iron mainly present as Fe(OH)2.