How many grams of KOH should be dissolved in water to make 2000.0 grams of a 10.0 ppm solution?

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.

"the periodic table is arranged in order of atomic number."