Question

How many grams of a stock solution that is 87.5 percent H2SO4 by mass would be needed to make 275 grams of a 55.0 percent by mass solution? Show all of the work needed to solve this problem.

Answer 1

Take a look into this beautiful part and you will get your answer
275 grams of a 55 per cent solution contains 0.55* 275 grams of pure H2SO4. We need to find the mass of 87.5 per cent solution which contains 0.55*275 grams H2SO4 this is (0.55* 275) / 0.875 grams. In that way you will have your answer. I hope this can help

Answer 2

The mass of sulfuric acid in the required solution is 55g per 100g of solution

We need to make total of 275 grams of solution of concentration 55%

So we need following amount of sulfuric acid in the solution

55% of 275  grams = 0.55 X 275 = 151.25 grams

Now we have a stock solution of sulfuric acid 87.5% (w/w)

It means in every 100g of solution 87.5g of sulfuric acid

We need 151.25 grams of sulfuric acid

87.5g of sulfuric acid will be obtained from 100g of stock solution

1g of sulfuric acid will be obtained from 100/87.5g of stock solution

151.25g of sulfuric acid will be obtained from = $\frac{100X151.25}{87.5}=172.85g$

Hence we will take 172.85 grams of stock solution to prepare 55% sulfuric acid solution of mass 275g

Rest we will take water.