How many moles are 25.0 mL of benzene (density 0.876 g/mL)?

There are 0.281 moles of benzene.

Explanation:

The density (δ) is the ratio between mass and volume of a compound. We obtain the mass of benzene using the density formula, then we calculate the weight of 1 mole of benzene (C6H6).

δ=m/v--> m=δxV= 0,876 g/ml x 25, 0 ml= 21, 9 g

Weight 1 mol C6H6= 6x(Weight C)+ 6x(Weight H) = 6 x 12 g+ 6 x 1g=78g/mol

78 g1 mol C6H6

21,9gx= (21, 9 g mol x1 mol C6H6)/ 78 g= 0,28076923 mol