front 1 Complete this statement: The P alkalinity is exactly half the T alkalinity, therefore ______ | back 1 All the alkalinity is in the carbonate form |
front 2 Calculate the cubic feet of media in the ion exchange softener using
the data given: | back 2 96 cu ft |
front 3 What is a disadvantage of ion exchange softening? | back 3 Disposal of spent brine |
front 4 What is a limitation of the lime-soda softening process? | back 4 Color removal may be complicated or impossible by the high pH levels |
front 5 What are potential hazards of using quicklime? | back 5 Heat is produced and splashes can cause severe caustic burns |
front 6 If the total hardness is greater than the total alkalinity, then | back 6 There is non-carbonate hardness present |
front 7 What is a benefit of the Split Treatment Process? | back 7 Recarbonation is unnecessary |
front 8 Calcium sulfate and magnesium sulfate are examples of what? | back 8 Non-carbonate hardness |
front 9 When lime is added to water to be softened and the pH is increasing, which chemical reaction will occur? | back 9 Alkalinity converts from the bicarbonate form to the carbonate form, and calcium is precipitated as calcium carbonate |
front 10 In ion exchange softening, what ions are exchanged? | back 10 Calcium and magesium for sodium |
front 11 What are the Maximum Contaminant Limits (MCL's) for calcium and magnesium in drinking water? | back 11 There are no MCLs for Ca or Mg |
front 12 At a pH value of 11.3, what has occurred? | back 12 The carbonate alkalinty has been converted to hydroxide |
front 13 Calculate the alkalinity constituents as mg/L of HCO3, CO3 and OH
using the following lab data: | back 13 HCO3= 0, CO3= 166, OH= 19 |
front 14 If the water alkalinity is equal to the water hardness, all of the hardness is | back 14 Carbonate hardness |
front 15 What is happening during the lime softening process at a pH of 11.3? | back 15 magnesium hydroxide precipitates |
front 16 How many milligrams of CO per liter will be present in a sample if the pH is greater than 8.3? | back 16 0 mg/L |
front 17 What is a common chemical used to remove non-carbonate hardness? | back 17 Sodium carbonate |
front 18 Which chemical can be used in place of soda ash, and in place of all or a part of the lime used to soften water? | back 18 Sodium hydroxide |
front 19 Water hardness is | back 19 A measure of the soap or detergent consuming power of water |
front 20 The lab analyst finds that the total alkalinity is the same as the
phenolphthalein alkalinity. Which equation below will be used to
calculate the alkalinity constituents? | back 20 P= T |
front 21 The operator has overdosed the recarbonation tanks with excess CO , causing the pH to rapidly decrease from 11 to 9. What is likely to occur? | back 21 Carbonate hardness will be re-established |
front 22 What ions cause a coating, or scale, to form inside the hot water heater similar to that in a tea kettle after repeated use | back 22 Calcium and magnesium |
front 23 Which statement about phenolphthalein alkalinity is correct? | back 23 If phenolphthalein is present, the pH will be above 8.3, and therefore no carbon dioxide can be present |
front 24 What is the purpose of adding CO2 to the softened water and bringing the pH down? | back 24 This prevents excessive scale buildup in filters, clearwells and distribution lines |
front 25 In the lime/soda softening process, what happens to CaCO3 after it is formed? | back 25 It settles out |
front 26 The operator of an ion exchange softening unit notices the effluent of the softener contains a hardness of one grain per gallon (1 gpg). What action should the operator take to correct the situation? | back 26 Nothing other than monitor the effluent hardness |
front 27 Which statement about hardness testing is true? | back 27 EDTA is used as a titrant to an end point that is pure blue color |
front 28 Split lime treatment can be used when the water contains what? | back 28 A high level of magnesium |
front 29 Convert a hardness of 280 mg/L to grains per gallon | back 29 16.4 gpg |