How much KCL would I need to add to 1 gallon of DI water to make a 2% solutiion?

Question

I need a 2% solution of Potassium chloride and DI water. How much KCL would I need to add to 1 gallon?

Answer 1

If it must be 2% weight by volume... you need 2 grams of KCl in 100 mL of solution. Assume little volume change upon dissolution, that is you get 2% solution when you mix 2 g of KCl with 100 mL of water.

Since 1gal=3.78L then you would need 2*3780/100=75.6grams of KCl.

If it is 2% weight by weight then: you have 2 g of KCl for every 98 grams of water. Hence, with water density at 1 g/mL you would need

2/98*1*3780=77.14 grams of KCl.