Other Chemistry Answers

A city’s water supply is fluoridated by adding NaF. The desired concentration of F

–

is

1.6 ppm. How many milligrams of NaF should be added per gallon of treated water if

the water supply already is 0.2 ppm in F

–? [Convert gallon to litres]

Katniss realizes that Prim’s recent exposure to President Snow’s rose garden has left her with Icysclerodermosis, a condition in which the skin on the arms and legs begins to harden and turn cold after contact with a specific poisonous rose. Deadly if left untreated, Katniss and Gale rush to find a cure. Katniss hears that Greasy Sae’s broth has been known to improve the circulation and speed recovery in the skin. Gale is told by others in the district that the mud from the mine could be the solution. They decide to test both possible cures to increase Prim’s chance of survival. Katniss feeds Prim broth while Gale applies the mud to Prim’s cold, hard skin. Both treatments are administered once daily. After a week of treatments, Prim’s skin returns to normal.

What is the initial observation?

A water sample has a methyl orange acidity of 60 mg/L. Calculate the quantity of lime in mg/L of CA(OH)2 required to raise the pH to 3.7?