Phosphorous trichloride can be formed via a combination reaction from its elements. phosphorous is often represented by its empirical formula, p, in chemical equations, as is carbon. if 12.39 g of phosphorous is combined with 42.54 g of chlorine, what mass of phosphorous trichloride could be formed?

Explanation:

We are given the masses of two reactants and asked to determine the mass of the product.

This looks like a limiting reactant problem.

1. Assemble the information

We will need a balanced equation with masses and molar masses, so let’s gather all the information in one place.  

MM:          30.97        70.91     137.33

                   2P     +     3Cl₂ ⟶ 2PCl₃

Mass/g:     12.39        42.54  

2. Calculate the moles of each reactant

3. Calculate the moles of PCl₃ from each reactant

4. Identify the limiting reactant

Cl₂ is the limiting reactant because it gives fewer moles of PCl₃

5. Calculate the mass of PCl₃