How many grams of ethanol (density 0.80 g/cm3) should be added to 5.0 g of chloroform (density 1.5 g/cm3) if the resulting mixture is to have a density of 1.2 g/cm3? Assume that the fluids do not change their volumes when they are mixed.

2.00 g of ethanol

Explanation:

The density of the mixture is the total mass (ethanol + chloroform) divided by the total volume. Let's call the mass of ethanol as x, the volume of it as V1, and the volume of chloroform as V2.

V2 = mass of chlorofrom/density

V2 = 5/1.5 = 3.33

x = density*volume

x = 0.8*V1

The density of the mixture will be:

(x + 5) / (V1 + V2) = 1.2

(0.8*V1 + 5) / (V1 + 5/1.5) = 1.2

0.8V1 + 5 = 1.2V1 + 4

0.4V1 = 1

V1 = 2.5 cm³

x = 0.8*2.5

x = 2.00 g