What is the density of an object with a mass of 1.663 g and a volume of 0.2009 mL

1.663g (Mass) : 0.2009mL (Volume) = 8.27775012g/mL

(or 8.2778 if you round to the fourth decimal place)

8.278 g/mL The definition of density is mass per volume. So what you need to do is divide the known mass by the known volume. So 1.663 g / 0.2009 mL = 8.27775 g/mL But you also have to keep track of significant figures. Since both 1.663 and 0.2009 have 4 significant figures each, you need to round the result to 4 significant figures. So 8.27775 g/mL = 8.278 g/mL