En un vaso se han puesto 250 g de alcohol junto con 2 g de yodo, que se disuelven completamente. Calcular la concentración de la disolución en % en masa.

The translation of the question is

250 g of alcohol have been put in a glass together with 2 g of iodine, which dissolve completely. Calculate the concentration of the solution in% by mass?

The %mass by mass of the given solution is 0.794%

Explanation:

We are given

Mass of solute(Iodine) = 2g

Mass of the solvent (Alcohol) = 250g

Since the Iodine dissolves completely in Alcohol

Total mass of the solution = 250 + 2 = 252g

the formula of concentration of the solution in  % by  Mass is given by

%

%w/W =

          = 0.794%

Therefore the %mass by mass of the given solution is 0.794%

law of conservation of matter

the density of gold = 19.3 g/cm3

the relation between density and mass and volume is

density = mass / volume

given :

mass of gold = 13 g

density = 13g / volume = 19.3

volume = 13 /19.3 = 0.67 cm^3

thus volume of gold nugget = 0.67 cm^3