Question

Determine the mass in grams of potassium chloride that must be added to 97 g of water to make a 1.09 m solution. Enter your answer to 2 decimal places.

Answer 1

Answer: 7.88 grams

Step-by-step explanation:

Molality of a solution is defined as the number of moles of solute dissolved per kg of the solvent.

`Molarity=(n)/(W_s)`

where,

n = moles of solute

`W_s` = weight of solvent in kg

moles of solute =
`\frac{\text {given mass}}{\text {molar mass}}=(xg)/(74.5g/mol)`

mass of solvent = 97 g = 0.097 kg (1kg=1000g)

Now put all the given values in the formula of molality, we get

`1.09=(x)/(74.5g/mol* 0.097kg)`

`x=7.88g`

Therefore, the mass in grams of potassium chloride that must be added to 97 g of water to make a 1.09 m solution is 7.88