Question

You need to make 700 mL of a 2.8 M KOH solution. How many grams of KOH should you measure out to make the solution?

Please show steps solution for this question to get the answer.

Answer 1

The answer is 109.76 g

Step-by-step explanation:

In order to find out the mass of KOH to be used we use the formula

m = c × M × v

where

m is the mass

c is the concentration in mol/dm³

M is the molar mass

v is the volume in dm³

From the question

c = 2.8 M

v = 700 mL = 0.7 dm³

Mr( K) = 39 , Mr(O) = 16 , Mr(H) = 1

we have

Molar mass of KOH = 39 + 16 + 1

= 56 g/mol

So we have

m = 2.8 × 56 × 0.7

We have the final answer as

109.76 g

Hope this helps you