Titration readings

You will write three small functions that turn burette readings into a concentration. Readings are in millilitres.

The idea. A titre is the final reading minus the initial reading. Two titres that agree within 0.10 mL are concordant. The unknown concentration comes from the ratio of the equation.

Your tasks.

1. Complete titre(start, finish). It returns the volume delivered, rounded to two decimal places.
2. Complete mean_concordant(titres). It returns the mean of the first two titres that agree within 0.10 mL, or None if no two agree.
3. Complete unknown_molarity(c_known, v_known, v_unknown, ratio). The reaction needs ratio moles of the unknown for each mole of the known substance. It returns the molarity of the unknown.