Answer:
We need 2 * 10^-2 grams (=0.02 grams) KOH
Explanation:
Step 1: Data given
Mass of solution = 2000.0 grams
Solution = 10.0 ppm
Step 2: Calculate mass KOH needed
A solution's concentration in parts per million tells you the number of grams of solute present for every 10^6 grams of the solution.
In this case, the target solution must have a concentration of
10.0 ppm , what means that it must contain 10.0 g of KOH( the solute), for every 10^6 grams of the solution
This means that the mass of KOH needed to make this solution is equal to
2000 grams * 10 grams KOH/ 10^6 grams solution = 0.02 = 2 *10^-2 grams
So, if you dissolve 2 *10^-2 grams of KOH in enough water to get a total mass of the solution to 2000.0 g , you will have a 10.0-ppm KOH solution.