4.4.4 - Mole Ratios In Equations

Question 1

What do the balancing numbers in a balanced equation for a reaction tell us !?

Answer 1

. How many moles of each reactant are needed
. How many moles of each product are made

Question 2

How do we calculate mass from mole ratio !?

Answer 2

. Convert the mass of X into moles of X
. Use the mole ratio from the balancing numbers
. Convert moles of Y into mass of Y

Question 3

What is a limiting substance !?

Answer 3

. If there isn’t enough

Question 4

What is a substance that is in excess !?

Answer 4

. If there is more than enough

Question 5

How to determine if a substance is limiting, or in excess!?

Answer 5

. The easiest way is to pick one (at random) then calculate how much of the other would be needed to react with it, and then compare that to how much of the other that actually is.

Question 6

Equation for percentage yield:

Answer 6

%yield = [experimental(smaller)➗theoretical]x100