Given:
m₁ = 1.70 kg, mass of the empty 3.00 L bottle
m₂ = 4.72 kg, the mass of the bottle and wine.
The mass of the wine is
m = m₂ - m₁ = 4.72 - 1.70 = 3.02 kg
Because the volume of the wine is 3.00 L, its density may be expressed as
(3.02 kg)/(3.00 L) = 1.0067 kg/L
The amount (density) of ethyl alcohol in the wine is
0.115*(1.0067 kg/L) = 0.1158 kg/L
In 250 mL of this wine, the mass of ethyl alcohol is
(250 x 10⁻³ L)*(0.1158 kg/L) = 0.02895 kg = 28.95 g
Answer: 28.95 g
