Question

Consider the following balanced equation:H₂SO4 (aq) + 2LiOH (aq) --> 2 H₂O (1) + Li₂SO4 (aq)A 33.98 mL sample of H₂SO4 is completely titrated with 18.19 mL of 1.35 M LIOH. What is the molarity of the H₂SO4?

Answer 1

1) Write the chemical equation.

`H_2SO_(4(aq))+2LiOH\rightarrow2H_2O+Li_2SO_4`

2) List the known and unknown quantities.

Sample: H2SO4

Volume: 33.98 mL.

Concentration: unknown

Titrant: LiOH

Volume: 18.19 mL = 0.01819

Concentration: 1.35 M

3) Find moles of LiOH

3.1- Set the equation

`M=\frac{moles\text{ }of\text{ }solute}{liters\text{ }of\text{ }solution}`

3.2- Plug in the values

`1.35\text{ }M=\frac{moles\text{ }of\text{ }solute}{0.01819\text{ }L}`
`moles\text{ }of\text{ }solute=1.35\text{ }M*0.01819\text{ }L`
`moles\text{ }LiOH=0.0245565`

The number of moles of LiOH in the reaction is 0.0246.

4) Find moles of H2SO4

The molar ratio between H2SO4 and LiOH is 1 mol H2SO4: 2 mol LiOH.

`mol\text{ }H_2SO_4=0.0246\text{ }mol\text{ }LiOH*\frac{1\text{ }mol\text{ }H_2SO_4}{2\text{ }mol\text{ }LiOH}`
`mol\text{ }H_2SO_4=0.01228\text{ }mol\text{ }H_2SO_4`

5) Molarity of H2SO4

Sample: H2SO4

Moles: 0.01228

Volume: 33.98 mL.

5.1- Convert mL to L.

1 L = 1000 mL

`L=33.98\text{ }mL*\frac{1\text{ }L}{1000\text{ }mL}=0.03398\text{ }L`

5.2- Set the equation to find molarity.

`M=\frac{moles\text{ }of\text{ }solute}{liters\text{ }of\text{ }solution}`
`M=\frac{0.01228\text{ }mol\text{ }H_2SO_4}{0.03398\text{ }L}`
`M=0.3614\text{ }M`

The molarity of the sample is 0.3614 M H2SO4.