Why is it important to test one substance at a time when doing an experiment?

Using a value of ksp = 1.8 x 10-2 for the reaction pbcl2 pb+2(aq) + 2cl -(aq). if the value of ksp was determined to be only 1.2 x 10-2: too much solid has dissolved. additional precipitate is forming. the solution is unsaturated. the ions are now combining to reduce their concentrations.

Ahydrogen atom has 1 electron. how many bonds can hydrogen form? a) 1 b) 2 c) 3 d) 4 e) 5

What state of matter is ice a. liquid b. element c. solid d. gas