Question | Answer |
Ability to resist changes in pH in response to dilute acids && act as buffers | ALKALINITY |
Chemical ions that form alkalinity are | HYXROXIDE, CARBONATE, BICARBONATE |
Metal ions that contribute to alkalinity | Calcium, Magnesium, Sodium, and Potassium |
End point | Phenomena in the chemical laboratory which has the following definition: a chemical is added drop by drop to a sample until a color change occurs |
Two types of alkalinity measurement | Total alkalinity && Phenolphthalein Alkalinity |
Laboratory Safety- Clothes | Never Work Alone && Protective Eye wear && Lab Coats && Gloves |
Laboratory Safety - Chemical | Proper storage and labeling && date && ventilated area |
Oxygen levels && Permissible | 19.5 to 23.5 % |
Methane levels && Permissible | <0.5 % |
Hydrogen Sulfide && Permissible | <10 ppm |
Carbon Dioxide && Permissible | <10,000 ppm |
Safe Drinking Water Act | 1974 && Passed as law in the same year |
Primary Contaminants | The contaminants identified by EPA as harmful to human health |
Maximum Contaminant Level M.C.L. | primary contaminants must not exceed certain specified levels known as M.C.L. |
Hardness | Mainly caused by Calcium and Magnesium |
Hard Water Standards | 100 mg/L in hardness |
Soft Water Standards | 60 mg/L in hardness |
Chromium Salt | used extensively for industrial processes and may enter a water supply through the discharge of waste |
Hexavalent Chromium Parameters | Holding Time - none
Preservation - 24 hours |
Spectrophotometry | quantitative measurement of the transmission properties as the function of wavelength |
Widely Distributed in Rocks and Soil | Manganese |
Manganese Spectrometer Reading | 525 nm |
Trace Amounts of chloride are eliminated by... | mercuric sulfate as a special reagent |
Ferrous Iron | Dissolved in Water |
Manganous Iron | Dissolved in Water |
Oxidized Iron... | forms iron rust |
A pressure chamber used to sterilize equipment and supplies by subjecting them to high pressure... | autoclave |
Used to measure the relative clarity of fluid by evaluating the amount of light scattered | Turbidimeter |
An instrument which measures the amount of light of a specified wavelength that passes through a medium | Spectrophotometer |
Sampling methos | A. Vital Part of studying the water quality
B. Source of Error in the process of obtaining water quality information |
Grab Sample | single water sample collected at no specific time |
Composite Sample | collection of individual samples obtained at regular intervals |
One of the most important aspects of laboratory procedures | Results are no better than the sample |
Preservation must be checked for the following characteristics | Required Volume
Type of Container
Preservation
Maximum Holding Time |
Separation methods | decanting, centrifuging, decanting, filtering |
Conductivity in water | ability of a water to conduct an electrical current |
Calcium Carbonate Saturation | industrial heat exchanges && domestic water heaters |
Over Saturated Calcium Carbonate in water | would form precipitate |
Under Saturation Calcium Carbonate in water | would dissolve |
Corrosive Water | pH && alkalinity tends to be slightly lower than 'stable' |
Calcium Carbonate Saturated Water | Neither precipitate nor dissolved |
Corrosive Water | undersaturated |
Super Saturated | Scale Deposit |
Zero Net Alkalinity | Stable Water |
Results in presence of metal ions in the water | Color |
Ways to remove true color from the water: | coagulation, chlorination, or ozonation |
Maximum Contaminant Levels For chlorine are... | 0.08 ppm |
Fast Chlorine Detection Method | DPD Method |
Higher Temperatures in DPD lead to... | false positive results |
Turbidity is removed by | distillation |
Fluoride Holding Time | 28 days |
Fluoride Spectrophotometer reading | 570 nm |
Chemicals Used For Fluoridation | Sodium Fluoride
Sodium Fluorosilicate
Fluorosilicic Acid |
Ways to remove alkalinity | Add hydrochloric or nitric acids |