Chem. 5.5 Limiting Reactant
What is theoretical yield?
Maximum amount of product you would expect from the reaction due to a reactant running out before the others.
What four questions are typically asked in limiting reactant problems?
1) Which reactant has been entirely consumed? 2) What mass of product can be formed? 3) What mass of the excessive reactant remains? 4) What percentage of the excessive reactant remains when the reaction is finished?
How do you answer this question: 3) What mass of the excessive reactant remains? How do you answer this question: 4) What percentage of the excessive reactant remains when the reaction is finished?
1. Use stoichiometry, starting with the limiting reactant, and work towards the excessive reactant 2. Take mass at start - mass consumed and it will = mass remaining 1. Take mass remaining/mass at start x 100= percent remaining
How can these two questions be answered: 1) Which reactant has been entirely consumed? 2) What mass of product can be formed?
1. Write out the balanced equation first 2. Use mass-mass problem-solving to find out which reactant would result in the least amount of product if completely consumed.
How is the mass of the theoretical yield determined?
The ___________________ produced by the limiting reactant is the ____________________ of the theoretical yield.
What about the other product?
What about the other product?
To solve for limiting and excess reactants, you will repeat the same stoichiometry steps using the same ___________________ in the chemical reaction for all _____________________.
product reactants
· Show how the limiting reactant is determined for 3.80 g of magnesium reacting with 12.5 g of oxygen.
see vid
How do the limits of reactants affect the outcome of chemical reactions?
the amount of productants is always limited by the amounts of available reactants.
VID. According to the video, how do you identify the limiting and excess reactants of a reaction?
the limiting reactant will run out first, the left over reactant is called the excess reactant
What is the excess reactant?
the reactant that is left over in chem reacti
What is a limiting reactant?
the reactant that runs out first
Describe limiting reactant problems.
there are given amounts of more than one reactant, and one will run out before the others. So, that reactant stops, or limits the reaction and it determines how much product can be made. -The reaction outcome: how much product gets made, and how much excess reactant is leftover
How do we use stoichiometry to help identify the limiting and excess reactants?
they can help us because they find which reactent is the limiting one
