Monitoring Chemical Reactions

Question 1

What is theoretical yield?
Equation for Theoretical Yield

Answer 1

Theoretical yield is the maximum possible mass of product that can be formed in a chemical reaction.
(Mass of limiting reactant/Mr of limiting reactant) * Mr of product = Theoretical Yield (g)

Question 2

What is percentage yield?
Equation for Percentage Yield

Answer 2

Percentage yield is the amount of the desired product produced compared to the theoretical yield of it.

(Actual Yield of Product/Theoretical Yield) * 100 = Percentage Yield

Question 3

What reasons prevent percentage yield from being 100%?

Answer 3

Reaction is reversible
Some reactant may be unexpected as unwanted products
Some products may be lost in handling
The reactants are impure
Some of the desired product is lost in separation

Question 4

What is atom economy?
Equation of Atom Economy

Answer 4

Atom economy is the measure of how many atoms in the reactants form a desired product.

( Mr of desired product (BN)/Mr of all products (BN) ) * 100 = Atom Economy

Question 5

What is the importance of atom economy?

Answer 5

Industrially, atom economy is important for lower costs for products and the removal of waste products, and sustainability. 100% atom economy is desirable but not always achievable.

Question 6

What is the molar gas volume?

Answer 6

The volume of one mole of any gas is 24 dm3 at room temperature (20) and pressure (1).
24 dm3 is known as the molar gas volume.

Question 7

How do you calculate the moles of gas?

Answer 7

NOM of gas = Volume of Gas (dm3) /// 24 dm3

Question 8

What is titration?

Answer 8

Titration is a technique that uses neutralisation to find the concentration of an acid or alkali.

Question 9

What are the steps to titration?

Answer 9

Known volume of alkali/acid added to conical flask using volumetric pipette called analyte.
Few drops of indicator called phenolphthalein
Acid/Alkali called titrant is added to the flask from burette until end point reached
Using titrant concentration and volume and analyte volume, calculate titre

Question 10

How do you calculate titre?

Answer 10

Convert cm3 to dm3
Use titrant volume and concentration to calculate moles
Use reactant to ratio moles
Use moles of analyte and known volume to calculate titre