Question

How do you determine the concentration of oxalic acid (using unit analysis) when you have the mass? do you need more information?

Answer 1

Concentration is generally expressed in terms of Molarity (M).

Molarity is the number of moles of solute dissolved in one liter of a solvent, i.e.

Molarity = moles of solute(n) / volume of solution (V) -----(1)

Here the solute is oxalic acid of known mass, m

Molar mass of oxalic acid (H2C2O4) = 90 g/mol

Number of moles, n = mass of oxalic acid/molar mass = m/90 ----(2)

Substituting for n in equation (1) we get:

M = 'm' gram /(90 gram.mole⁻¹) * ('V' Lit)

M = (m/90*V) mole/Lit

Since the mass of oxalic is known, the volume V is required to complete the molarity/concentration calculation.