Question

What mass of K2SO4 would you measure out to prepare 550 ml of a 0.76 M solution

Answer 1

The molecular weight of K2SO4 is 174.26 g/mole. The mass of K2SO4 required to make this solution is calculated in the following way. 
550mL * (0.76mole/1000mL) * (174.26g/mole) = 72.84gram
I hope this helps.

Answer 2

Answer:

$m_{K_2SO_4}=72.84gK_2SO_4$

Explanation:

Hello,

In this case, by considering that the both the volume of the solution of potassium sulfate and its concentration are given, one solves for the required mass considering the following proportional factors related stoichiometrically:

$m_{K_2SO_4}=550mLsln*\frac{1Lsln}{1000mLsln}*0.76\frac{molK_2SO_4}{Lsln}*\frac{174.259gK_2SO_4}{1molK_2SO_4}\\ m_{K_2SO_4}=72.84gK_2SO_4$

Best regards.