Question

Prepare 250 cm3 2M NAOH: molar mass M = 40g/mol. calculate substance mass​

Answer 1

Answer: The mass of the substance is 20 g

Step-by-step explanation:

Molarity of a solution is defined as the number of moles of solute dissolved per liter of the solution.

`Molarity=(n* 1000)/(V_s)`

where,

n = moles of solute

`V_s` = volume of solution in ml = 250 ml
`(1cm^3=1ml)`

moles of
`NaOH` =
`\frac{\text {given mass}}{\text {Molar mass}}=(xg)/(40g/mol)`

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

`2=(x* 1000)/(40* 250)`

`x=20g`

Therefore, the mass of the substance is 20 g