How do I do both of these?

9. write the chemical equation for the following word equations. include symbols for physical states in the equation. a. solid zinc sulfide + oxygen gas -> solid zinc oxide + sulfur dioxide gas b. aqueous hydrochloric acid + aqueous barium hydroxide -> aqueous barium chloride + water

Significant figures are digits read directly from the measuring instrument plus one more digit, which is __ by the observer.

How is the atomic number of a nucleus changed by alpha decay