Topic 3 - Quantitative Chemistry Flashcards
Concentration
- A measure of how crowded things are
- The amount of a substance (e.g. mass or the number of moles) in a certain volume of a solution is called the concentration
- The more solute there is in a given volume, the more concentrated the solution
How to calculate concentration (g/dm3)
Concentration (g/dm3) = mass of solute (g) / volume of solvent (dm3)
How to calculate concentration (mol/dm3)
Concentration (mol/dm3) = number of moles of solute (mol) / volume of solvent (dm3)
1dm3
1000cm3
How to convert cm3 to dm3
Divide by 1000
Summary of atom economy
- % of reactants forming useful products
- Tells you how much of the mass of the reactants is wasted when manufacturing a chemical, and how much ends up as he desired product
What does 100% atom economy mean?
All the atoms in a reaction have been turned into the desired product
The higher the atom economy…
The ‘greener’ the desired product
Formula for atom economy
Relative formula mass of desired product
———————————— x 100
Relative formula mass of all reactants
HIGH ATOM ECONOMY
- Better for profits and the environment
- Reactions w/ the highest economy are the ones that only have one product, these reactions have an atom economy of 100%
LOW ATOM ECONOMY
- Reactions w/ low atom economy use up resources v quickly
- Makes lots of waste, expensive to remove and dispose responsibly
- waste materials tend to make reactions unsustainable, if raw materials are non-renewable they’ll run out
- Low atom economy reactions may not be profitable, raw materials are expensive to buy
How to resolve the problem of lots of waste products produced by a reaction with a low atom economy:
- Find a use for the waste products rather than throwing them away
- There’s often more than way to make desired product, come up w/ a reaction that gives useful byproducts instead of useless ones
