Unit 3-Getting The Most From Reactants

Question 1

Give examples of factors influencing industrial process design.

Answer 1

• availability, sustainability and cost of feedstock(s)
• opportunities for recycling
• energy requirements
• marketability of by‑products
• product yield

Question 2

Give examples of environmental factors influencing industrial process design.

Answer 2

• minimising waste
• avoiding the use or production of toxic substances
• designing products to biodegrade when appropriate

Question 3

Why are balanced equations important for reactions?

Answer 3

Balanced equations show the mole ratios of reactants and products.

Question 4

What is meant by the molar volume of a gas?

Answer 4

The molar volume is the volume occupied by one mole of any gas at a certain temperature and pressure.

Question 5

What are the units of molar volume?

Answer 5

l mol^-1

Question 6

What affects the value of the molar volume?

Answer 6

Temperature and pressure.

Question 7

How is the number of moles calculated from mass and GFM?

Answer 7

n = m/GFM

Question 8

How is the number of moles calculated from concentration and volume?

Answer 8

n = c x V

Question 9

What is meant by an excess reactant?

Answer 9

A reactant is in excess when there is more than enough of it to react.
The other reactant becomes the limiting reactant, which determines the quantity of product formed.

Question 10

How is percentage yield calculated?

Answer 10

% Yield = actual yield/theoretical yield x 100

Question 11

What does a higher percentage yield show about a reaction’s efficiency?

Answer 11

The higher the percentage yield is, the higher the efficiency.

Question 12

What does a reaction’s atom economy show?

Answer 12

Atom economy measures the proportion of the mass of reactants that ends up in the desired product.

Question 13

How is atom economy calculated?

Answer 13

% atom economy = mass of desired product / total mass of reactants x 100