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28 votes
Which reactant controls the amount of product formed?.

User Bentley
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2 Answers

18 votes
18 votes

Answer:

Limiting Reagent or Limiting Reactant

Step-by-step explanation:

  • The limiting reagent of a reaction is the reactant that runs out first. Once it is completely consumed, the reaction stops.
  • The limiting reagent is the only chemical that is used to calculate the theoretical yield. It is used up first. After that, any excess reagent will not be able to produce more products.

And to assess which reactant is which, we must usually have quantities of each reagent in a chemical reaction...and of course we should write a stoichiometric equation that is balanced with respect to mass and charge in order to assess the stoichiometric equivalence.

We could examine for instance, the combustion of methane gas, the which MAY have cooked your dinner … its combustion reaction is as shown...


CH_4(g) + 2O_2(g) rarr CO_2(g) + 2H_2O(g) + Delta

And here conditions of COMPLETE combustion pertain; there is DIOXYGEN in excess, AND methane is the limiting reagent. A
10*g mass of methane represents a molar quantity of …


(10.0*g)/(16.01*g*mol^-1)=0.623*mol

And with respect to dioxygen we thus require...


0.623*mol*32.00*g*mol^-1=40*g

...but this quantity (AND MORE) is available from the atmosphere....and the methane was the limiting reagent....

User Phil Parker
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3.4k points
5 votes
5 votes

Answer:

limiting reactant gives ................

User TheQueenIsDead
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