Question

What mass of KCl will produce a saturated solution in 500.0 g of water at 20°C? The solubility of KCl at 20°C is 34.0 g/100 g H2O.

Answer 1

34g -------- 100g H₂O
Xg ---------- 500g H₂O
X = (500×34)/100
X = 170g KCl

:)

Answer 2

170 g of KCl will produce a saturated solution in 500 g of water at 20 ° C

Step-by-step explanation:

The rule of three or is a way of solving problems of proportionality between three known values and an unknown value, establishing a relationship of proportionality between all of them. That is, what is intended with it is to find the fourth term of a proportion knowing the other three. Remember that proportionality is a constant relationship or ratio between different magnitudes.

If the relationship between the magnitudes is direct, that is, when one magnitude increases, so does the other (or when one magnitude decreases, so does the other) , the direct rule of three must be applied. To solve a direct rule of three, the following formula must be followed:

a ⇒ b

c ⇒ x

Then

`x=(c*b)/(a)`

Solubility is the measure of the ability of a certain substance to dissolve in another. In this case the solubility of KCl at 20 ° C indicates that 34.0 g dissolve in 100 g H2O at the mentioned temperature. Then it is possible to apply a rule of three to know the mass of KCl will produce a saturated solution in 500 g of water at 20 ° C: if in 100 g of H2O 34 g of KCl will dissolve, in 500 g of H2O how much mass of KCl will dissolve ?

`mass of KCl=(500 g H2O*34 g KCl)/(100 g H2O)`

mass of KCl=170 g

Then, 170 g of KCl will produce a saturated solution in 500 g of water at 20 ° C