From masses to a formula

You will write functions for the analysis of an organic compound: the per cent of carbon and hydrogen from the masses of carbon dioxide and water, the per cent of nitrogen by the Kjeldahl method, and the empirical formula from the percentages.

The idea. $12$ g of carbon in every $44$ g of carbon dioxide, and $2$ g of hydrogen in every $18$ g of water. For nitrogen, $\%\text{N} = \dfrac{1.4\, M b V}{m}$. For the formula, divide each per cent by the atomic mass, and then by the smallest answer.

Your tasks.

1. Complete percent_carbon(sample, co2) and percent_hydrogen(sample, water).
2. Complete kjeldahl(sample, molarity, volume, basicity).
3. Complete empirical(percents): return a dictionary with the whole number ratio of the atoms, from masses.