. In an investigation, the volume of a material is measured
as 80.0 cm3 and its mass is measured as 253 g. Which
calculation of density correctly uses the precision rules:
3.1625 g/cm3, 3.163 g/cm3, 3.16 g/cm3, 3.2 g/cm3, or 3
g/cm3?

3.2 g/cm3

Explanation:

Mass = 253 g

Volume = 80.0 cm3

Density = Mass / Volume = 253 g / 80.0 cm3

Density = 3.1625 g/cm3

The precision rule means the answer must not have more significant values than the value with the least number of significant figures. In this case, the value with the least number of significant figures is 80.0  with two signiificant figures. Hence;

Answer = 3.2 g/cm3

b. examine and describe cells

a polar bond is formed when electrons are shared unevenly between atoms