What are the rules for rounding off the results of calculations?

Solution 29E: (a) Density defines as the ratio of mass to volume of a substance. Density = Mass/volume Given, mass = 40.55 g and volume = 25.0 ml Density = 40.55 g/25 mL = 1.622 g/mL Thus, the density of tetrachloroethylene is found as 1.62 g/mL. Whereas The density of water is 1.0 g/mL Since density is directly proportional to mass of the following substance, Since, if density of a substance is...