Select the correct answer.

which statement best explains how electrons form a covalent bond in a molecule?

a.

a pair of electrons splits so that each atom gets one electron.

b.

a pair of electrons belongs to two atoms at the same time.

c.

a pair of electrons is transferred from one atom to another atom.

d.

a pair of electrons moves from a lower energy level to a higher energy level.

e.

a pair of electrons drifts freely from one molecule to another.

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.)

If you need to add 27.50ml of a solution, which piece of glassware would you use to deliver this volume and explain how you would determine if the 27.50 ml was measured?

Which order shows the levels of organization from largest to smallest? organism, organ system, cell, organ, tissue organism, tissue, organ system, organ, cell organism, organ, organ system, cell, tissue organism, organ system, organ, tissue, cell