Question 5 Which of the following species is not part of the carbonate system? carbonate carbon dioxide O calcium carbonate 5 pts bicarbonate O carbolic acid Question 6 About how much of the drinking water used in the United States comes from groundwater sources? O 35% 50% O 25% 65% 75% Question 7 The chemicals commonly added to treat water hardness are O calcium hydroxide and magnesium hydroxide sodium bicarbonate and calcium hydroxide O calcium hydroxide and sodium carbonate sodium bicarbonate and magnesium hydroxide O sodium carbonate and magnesium hydroxide 5 pts 5 pts Question 8 5 pts Recarbonation is used during water softening treatment to provide carbonate for the precipitation of calcium carbonate solids. provide the municipality with "sparkling water". disinfect the water before storage and delivery. O lower the treated water pH into the EPA-allowed pH = 6 to 9 range. strip the water of toxic or noxious gases before storage and delivery