C. What is the volume of a rock that has a mass of 75.4 grams and
a density of 3.45g/cm??

75.4 gram /3.45 gram/cubic centimeter  = 21.855072463768 cubic centimeter

Explanation:

V =   m /ρ

where V = Volume, p = Density  and m = Mass

nacl or sodium chloride is an ionic compound. this is because an ionic compound pertains to a compound that consists of positively and negatively charged ions. in this case, na (sodium) has a tendency to lose one electron when it reacts with with other atoms, so the resulting sodium ion contains 11 protons and 10 electrons, thus making it positively charged (na+), when chlorine reacts, it usually gains one electron to form an ion called chloride, thus making it negatively charged ( since the ions are oppositely charged, they attract.