3.4

Question 1

Percentage yield equation

Answer 1

(Actual yield / theoretical yield) x 100

Question 2

Limiting reagent definition

Answer 2

The reactant that is not in excess, that will be used up first and stop the reaction

Question 3

How to work out which reactant is limiting reactant

Answer 3

Balance equation
Then ask, if you had same amounts of each reactant, which would run out first?
The one that runs out first is the limiting resctant, the other one is in excess.
For example:

2H2 + O2 —> 2H2O

If you had both 1mol of H2 and O2, the H2 would run out first, and youd still have 0.5mol O2 left, so H2 is limiting, O2 is excess

Question 4

Atom economy of a reation is a measure of…

Answer 4

How well the atoms have been utilised

Question 5

Reactions with high atom economies…

Answer 5

Produce large proportion desired products, few unwanted waste products

Are important for sustainability as they make the best use of natural resources

Question 6

Arom economy assumes a ___% yield

Answer 6

100%

Question 7

The chemical equation of the reaction has to be _________ to work out atom economy

Answer 7

BALANCED

Question 8

Equation for atom economy

Answer 8

Atom economy = (sum of molar masses of desired products/sum of molar masses of all products) x 100

Question 9

3 quick benefits of high atom economy

Answer 9

Industrial processes more efficient
Preserves raw materials
Reduces waste