Yield of a two-step route

You will write three small functions for a preparation in two steps, such as toluene to benzal chloride to benzaldehyde. They find the moles, the theoretical mass and the overall mass obtained.

The idea. Moles are mass divided by molar mass. The theoretical mass of the product is the moles times the molar mass of the product. The mass obtained is the theoretical mass times every step yield, each as a fraction.

Your tasks.

1. Complete moles(mass, molar_mass).
2. Complete theoretical(mass_start, molar_start, molar_product) so that it returns the mass of product for a one to one reaction.
3. Complete obtained(mass_start, molar_start, molar_product, yields), where yields is a list of percentages, one for each step.