Final answer:
To calculate the excess reactant left over after boron reacts with chlorine, the balanced chemical equation and molar masses are needed to determine the number of moles of each reactant. Without this information, we assume boron is the limiting reagent and use stoichiometry to calculate the excess chlorine remaining, if 3 moles were initially used.
Step-by-step explanation:
To determine the amount of excess reactant left over after boron has completely reacted with chlorine gas, we first need to establish the stoichiometry of the reaction. The balanced chemical equation for this reaction is necessary for calculation, but since it's not provided, we can assume a generic reaction where one mole of boron reacts with a certain number of moles of chlorine to produce a boron-chlorine compound.
Next, we would calculate the number of moles of each reactant using their given masses and molar masses. For this specific question, more information is required, such as the balanced chemical equation and the molar masses of boron and chlorine to carry out the calculations. If boron is the limiting reactant, then the theoretical yield of product is dictated by the moles of boron used. Any remaining chlorine would be in excess.
Lastly, if we knew that 3 moles of chlorine were originally used, as per the reference information provided, and boron is the limiting reagent, then (14 - 3) = 11 moles of chlorine would remain.