I need to know how to do all the levels of the worksheet

Which of the following elements is a representative element? a. chromium (cr) b. aluminum (al) c. mercury (hg) d. silver (ag)

Which of the following statements about acidic water is true? a. acid has no effect on the h, o molecules. b. the solution contains a larger number of oh ions than h, o ions. c. the solution contains a larger number of h, o ions than qh ions. d. the solution contains an equal number of h, o ions and oh ions. none of the above e.

How many miles of water are produced if 5.43 mol pbo2 are consumed