quantitative chemistry - Chemistry Flashcards
1
Q
What is the equation to atom economy?
A
Mr of desired product
atom economy = —————————— x100
Mr of reactants
2
Q
What is the definition of atom economy?
A
the amount of reactants end up as the desired product
3
Q
What would be the atom economy of this equation, the desired product being ammonia?
N₃ + 3H₂ → 2NH₃
A
100%
4
Q
Give 4 reasons why it is important to consider atom economy
A
- raw materials are expensive, if most of the reactants get turned to waste, then reaction is less profitable
- less sustainable to produce small amounts of desired products from large amounts of reactants
- waste products can be expensive to get rid of
- waste products can damage the environment
5
Q
What are some factors that affect how profitable a reaction is?
A
- percentage yield
- cost of raw materials
- rate of reaction
- position of equilibrium
- cost of maintaining the right conditions
6
Q
Give 3 reasons why the percentage yield of a reaction is not always 100%
A
- reactants might not react
- some of the reactants/products could be stuck on equipment
- some of the reactants could undergo a separate reaction, leaving to a different product
7
Q
What is the equation to percentage yield?
A
actual yield
percentage yield = ———————– x100
theoretical yield
