Question

A 1.268 g sample of a metal carbonate (MCO3)was treated with 100.00 mL of 0.1083 M sulfuric acid (H2SO4), yielding CO2 gas and an aqueous solution of the metal sulfate (MSO4). The solution was boiled to remove all the dissolved CO2 and was then titrated with 1.241×10⁻² MNaOH. A 91.86 mL volume of NaOH was required to neutralize the excess H2SO4.

A) What is the identity of the metal M?

B) How many liters of CO2 gas were produced if the density of CO2 is 1.799 g/L?

Answer 1

Total moles H₂SO₄ = (molarity H₂SO₄) * (volume H₂SO₄ in Liter)

Total moles H₂SO₄ = (0.1083 M) * (0.100 L)

Total moles H₂SO₄ = 0.01083 mol

moles NaOH used = (molarity NaOH) * (volume NaOH in Liter)

moles NaOH used = (1.241 x 10^-2 M) * (91.86 x 10^-3 L)

moles NaOH used = 1.14 x 10^-3 mol

moles H₂SO₄ consumed by NaOH = (1/2) * (moles NaOH)

moles H₂SO₄ consumed by NaOH = (0.5) * (1.14 x 10^-3 mol)

moles H₂SO₄ consumed by NaOH = 5.70 x 10^-4 mol

moles consumed by metal carbonate = (Total moles H₂SO₄) - (moles H₂SO₄ consumed by NaOH)

moles consumed by metal carbonate = (0.01083 mol) - (5.70 x 10^-4 mol)

moles consumed by metal carbonate = 0.01026 mol

moles MCO₃ present = moles consumed by metal carbonate

moles MCO₃ present = 0.01026 mol

molar mass MCO₃ = (mass MCO₃) / (moles MCO₃ present)

molar mass MCO₃ = (1.268 g) / (0.01026 mol)

molar mass MCO₃ = 123.6 g/mol

molar mass M = molar mass MCO₃ - [(molar mass C) + 3 * (molar mass O)]

molar mass M = 123.6 g/mol - [(12.0 g/mol) + 3 * (16.0 g/mol)]

molar mass M = 63.6 g/mol

Identity of metal M is Copper (Cu)

(B) moles CO₂ formed = moles MCO₃

moles CO₂ formed = 0.01026 mol

mass CO₂ formed = (moles CO₂ formed) * (molar mass CO₂)

mass CO₂ formed = (0.01026 mol) * (44.0 g/mol)

mass CO₂ formed = 0.45144 g

volume CO₂ formed = (mass CO₂ formed) / (density CO₂)

volume CO₂ formed = (0.45144 g) / (1.799 g/L)

volume CO₂ formed = 0.251 L