Part A:
Given:
The volume of acetone, V=17.96 mL.
We know, the density of acetone is D=0.7900 g/mL.
Now, the mass of acetone is,
[tex]\begin{gathered} M=VD \\ =17.96mL\times0.7900\text{ g/mL} \\ =14.19\text{ g} \end{gathered}[/tex]Therefore, the mass in grams of acetone upto four significant figures is 14.19g.
Part B.
Given:
The mass of acetone, M=7.40 g.
The volume is,
[tex]\begin{gathered} V=\frac{M}{D} \\ =\frac{7.40\text{ g}}{0.7900\text{ g/mL}} \\ =9.37\text{ mL} \end{gathered}[/tex]Therefore, the volume in mL upto three significant figures is is 9.37 mL