Chapter 5D - Compromise Conditions

Question 1

Define Compromise Conditions

Answer 1

Conditions that may not give the best yield of product but are the most economically viable in terms of cost of production and reaction rate

Question 2

Define Decarbonisation

Answer 2

The process of reducing/elimination of CO2 and other greenhouse gases

Question 3

Define Green Hydrogen

Answer 3

hydrogen gas produced using renewable energy sources e.g. wind/solar power through electrolysis

Question 4

Define Grey Hydrogen

Answer 4

Hydrogen produced through steam methane reforming (SMR)

Question 5

Define Side Reaction

Answer 5

A reaction that occurs at the same time as the main reaction leading to the formation of side products and lower yield of the main product.

Question 6

Why are compromise conditions used?

Answer 6

Times where a conflict exists between the equilibrium yield and reaction rate

Question 7

What can catalysts be used for specifically?

Answer 7

• optimise the formation of reaction products by increasing reaction rate
• reduce the formation of unwanted side products (minimise side reactions)
• improves efficiency of the manufacturing process for desired reaction

Question 8

How can catalysts be used to optimise product formation (exothermic)

Answer 8

• low temperatures lead to higher yield while high temperatures lead to higher rate of reaction
• catalysts reduce activation energy increasing reaction rate
• reduces the energy input required, making process more energy efficient

Question 9

Describe the sustainability of catalysts

Answer 9

• Can undergo physical changes and become less effective hence replaced
• this does not mean the catalust has been consumed
• Recycling catalysts improves sustainability

Question 10

Why should we recycle catalysts?

Answer 10

• allows for preservation of earth’s finite resources
• mining catalysts extremely difficult and requires great energy
• reduces amount of waste sent to landfill

Question 11

Define Economically Viable

Answer 11

Project with overall positive net economic contribution to society after all costs and benefits are accounted for

Question 12

Why are side reactions undesirable?

Answer 12

• high temperatures increases the risk of side reactions taking place
• irreversible, the amount of unwanted products increase while the amount of available reactants decreases
• can destroy production of equipment hence catalysts extend the lifetime of equipment

Question 13

What is the key consideration in optimising formation of equilibrium reaction products?

Answer 13

• Energy efficiency
• Focus on energy consumption not energy production

Question 14

How do catalysts improve energy efficiency?

Answer 14

• increase rate of reaction instead of high temperatures
• reducing the energy input
• better for the economy/environment
• lower temperatures are less expensive and require less energy to maintain

Question 15

How do heat exchangers improve energy efficiency?

Answer 15

• recover wasted heat from exothermic reactions carried out on a large scale
• transfer heat from one place to another
• heat is recovered and reused to continue powering the reaction
• reduces energy input requirements