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# Sulfric acid H2SO4

A 0.21g sample of sulfuric acid is dissolved completely in water to make 0.25 litre of final solution. Calculate the hydrogen ion concentration in mol 1 - 1 in this solution. In scientific notation and significant figures.

#### Solution Preview

N.B. The symbol "^" indicates superscript.

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Step 1: Determine the molar mass of sulfuric acid, H2SO4.

There are 2 hydrogens: 2 x 1.008 = 2.016
There is 1 sulfur: 32.06
There are 4 oxygens: 4 x 16.00 = 64.00

Total mass is 98.08 g/mol.

Step 2: Determine the number of moles in 0.21 g of sulfuric acid.

(0.21 g)(1 mol/98.08 g) = 0.0021 mol = 2.1x10^-3 mol

(Notice that we only have two significant figures at this point since 0.21 only has two.)

Step 3: Determine the molarity of the solution.

(2.1x10^-3 mol)/(0.25 L) = 8.4x10^-3 ...

#### Solution Summary

The solution calculates the hydrogen ion concentration in mol 1-1 of a sulfric acid and water solution. Scientific notation and significant figures are given.

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