If the standard reduction potential of a half-cell is positive, which redox reaction is spontaneous when paired with a hydrogen electrode?

A. oxidation

B. both reduction and oxidation

C. reduction

D. neither reduction nor oxidation

Why are people not able to scuba dive in the deep part of the ocean

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.)

The number of neutrons is equal to the atomic number minus the atomic mass. a. true b. false