Chemistry 122 d

Question

Calculate the volume of 0.18 M NaOH needed to react completely with 20.0 mL of 0.45 M H2SO4

H2SO4(aq) + 2NaOH(aq) -> Na2SO4(aq) + 2H-OH(l)

L L

mol/L mol/L

mol mol

(its a chart)

Answer 1

To calculate the volume of NaOH, let's start with what we are given, H₂SO₄

20.0 mL = 0.0200 L H₂SO₄ , since M = mol/L

Calculate the moles of H₂SO₄ :

0.45 mol/L H₂SO₄ × 0.0200 L H₂SO₄ = 0.0090 mol H₂SO₄

From the balanced equation, it takes 1 moles of H₂SO₄ to react with with 2 moles of NaOH. So we can create a ratio:

2 mol NaOH / 1 mol H₂SO₄

Use this ratio to solve for the moles of NaOH needed to react completely with H₂SO₄

0.0090 mol H₂SO₄ × (2 mol NaOH / 1 mol H₂SO₄) = 0.018 mol NaOH

Now that we have the moles and concentration of NaOH, solve for volume:

0.018 mol NaOH / 0.18 mol/L NaOH = 0.10 L NaOH

100 mL NaOH