True or false a chemical bond occurs when atoms lose gain or share electrons

Note the ph and poh values labeled with letters on the ph scale below. based on log rules and the way ph is calculated, what is the difference in [oh– ] concentration between point a and point b. a) 10^1 b) 10^5 c) 10^6 d) 10^7

Ais a mountain created from eruptions of lava, ash, rocks, and hot gases.

Modern pennies are composed of zinc coated with copper. a student determines the mass of a penny to be 2.482 g and then makes several scratches in the copper coaling (to expose the underlying zinc). the student puts the scratched penny in hydrochloric acid, where the following reaction occurs between the zinc and the hcl (the copper remains undissolved): zn(s) + 2 hcl(aq) → h2(g) + zncl(aq)the student collects the hydrogen produced over water at 25 °c. the collected gas occupies a volume of 0.899 l at a total pressure of 79 j mmhg. calculate the percent zinc (by mass) in the penny. (assume that all the zn in the penny dissolves.)