Question

en un recipiente se tiene 800 g de una solución al 35% en masa de ácido sulfuroso, de la cual se evapora 80ml de agua. ¿cuál es el porcentaje en masa de ácido sulfuroso en la nueva solución? dato: densidad del agua es 1g/ml.

Answer 1

The mass percent of sulfurous acid in the new solution : 38.9%

Further explanation

In a container you have 800 g of a 35% by mass solution of sulfurous acid, from which 80 ml of water evaporates. What is the mass percent of sulfurous acid in the new solution? data: density of water is 1g / ml.

solution 1

composition :

• 35% acid :

$\tt 0.35\times 800~g=280~g$

• water :

$\tt 800-280=520~g$

solution 2(new solution)

composition :

• water

$\tt 520-(80~ml\times 1~g/ml)=440~g$

• Total mass of new solution after water evaporated

$\tt 280(acid)+440(water)=720~g$

• %mass of acid in a new solution

$\tt \dfrac{280}{720}\times 100\%=38.9\%$