Applying the rules of significant figures, which of the following would be the correct value for the density of a substance which has a mass if 32.40 g and a volume of 2.0mL? 16.20 g/mL
16 g/mL
0.06 g/mL
5.00 g/mL

16 g/ml

Given

mass = 32.40 g

volume = 2.0mL

Required

Density

Solution

Density is a quantity derived from the mass and volume  

Density is the ratio of mass per unit volume  

Density formula:  

ρ = density  

m = mass  

v = volume  

Input the value :

ρ = 32.40 g / 2.0 ml

ρ = 16.2 g/ml

Rules for division: The least number of significant figures in the problem determines the number of significant figures in the answer.

32.40 = 4 sig.fig

2.0 = 2 sig fig

The answer must be 2 sig fig

So the answer = 16 g/ml

when the volume of gas is   changed from   717.73 ml   to 852 ml   the temperature will   change   from 315   c to 452   c

    calculation

this is calculated using the charles law formula

that is,   v1/t1 = v2/t2

          v1=?

        t1 = 315 c   into   kelvin = 315 +273 = 588 k

        v2 = 852   ml

        t2 = 425c + 273 =698 k

make v1   the subject of the formula ( by   multiplying both side by t1)

  v1=( v2 xt1) / t2

v1= (852 ml   x 588 k)/ 698 k= 717.73 ml

a is the correct answer