cwea Grade 4 Test Part 2

cwea Grade 4 Test Part 2 Acid: - Correct Answer A substance which releases hydrogen ions when dissolved in water. Most acids will dissolve the common metals and will react with a base to form a neutral salt and water. An acid is the opposite of an alkali, has a pH rating lower than 7.0, will turn litmus paper red, and has a sour taste. Acidity: - Correct Answer The quantitative capacity of water or a water solution to neutralize an alkali or base. It is usually measured by titration with a standard solution of sodium hydroxide, and is expressed in ppm or mg/L of its calcium carbonate equivalent. Accuracy: - Correct Answer The difference between the readings of an instrument and true value of what is being measured, expressed as a percent of full instrument scale. Air Gap: - Correct Answer A clear vertical space through the free atmosphere, between the lowest opening of any pipe or faucet conveying water or waste to a tank plumbing fixture receptor or other device, and the flood level rim of the receptacle. An air gap is used to prevent cross connection between a water treatment device and a possible source of wastewater, thereby preventing a reverse flow of water from the sewer into the water supply system. Without an air gap, such reverse flow could occur due to an increase in the pressure in the sewer system or the creation of a negative pressure in the water supply line. Local plumbing codes usually require the air gap to be twice the diameter of the inlet, with a minimum width of 1.5 inches. Alternating current (AC Power): - Correct Answer Electrical current that alternates direction in cycles called hertz. American Wire Gage (AWG): The U.S. standard for wire size. Alkalinity: - Correct Answer The quantitative capacity of water to neutralize an acid; that is, the measure of how much acid can be added to a liquid without causing a significant change in pH. Alkalinity is not the same as pH because water does not have to