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let us substitute them in the formula to find out the molar

concentration

The molar mass M of (H 2SO 4) equals 98 g/mol. According to the

formula,

let us assume that the solution mass is 100 g, then the mass of

the dissolved substance is 15 g. Substituting the value in the above

formula we have the following equation:

3
Answer:: С m(H 2SO 4) = 1,6837mol/dm .

Example 4. What mass ratio is needed to mix 14% and 56% sulfate acid

solutions to prepare a 20% solution?

Solution: Using the rule of the cross the scheme is made up:

56 6 20 – 14 = 6
20
14 36 56 – 20 = 36

Each difference shows the mass fractions of the solution whose mass fraction

is written on the same horizontal. So, to prepare a 20% solution one needs to take

6 parts of 56% and 36 parts of 14% solution.

Answer: 6 mass fractions of 56% and 36 mass fractions of 14% solution.

Example 5. Determine the pH of the 0.03 M solution of HCl.

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