Amount of substance Flashcards
Standard conditions
- 25 degrees celsius or 298k
- 100kp or 1atm
- 1moldm^3
Number of moles for solid
n =m/mr
number of moles for a gas
n = V/24dm^3 or 24000cm^3
number of moles for liquids
n = c x v
ideal gas equation
pV = nRT
Units for pressure, volume, temperature, ideal gas constant
pressure - Pa
volume - m^3
temperature- k
ideal gas constant - 8.314
Convert cm^3 to m^3
multiply by 10 to the power of minus 6
Convert dm^3 to m^3
multiply by 10 to the power of minus 3
Convert degrees to kelvin
+273
convert Kpa to Pa
multiply by 10 to the power of 3
Amount of substance
Used to count the number of particles in a substance.
Definition of mole
The amount of a substance that contains 6.02 x 10^23 particles.
Avogadro constant
The number of particles in each mole of carbon -12.
Empirical formula
The simplest whole number ratio of atoms of each element in a compound.
Molecular formula
The number of atoms of each element in a molecule.
Hydrated
A crystalline compound that contains water molecules.
Anhydrous
A crystalline compound containing no water molecules.
Water of crystallisation
Water molecules that form part of the crystalline structure of a compound .
Molar mass
Mass in g in each mole of substance
Standard solution
Solution of a known concentration.
Stoichiometry
A ratio of amount/moles of each substance in balanced equation.
Theoretical yield
Maximum possible product if all reactants have reacted and converted to product.
Why may you not achieve theoretical yield?
- Reaction may not go to completion
- Side reactions may take place
- Purifications may lead to loss of product
Formula for percentage yield
Actual yield/ theoretical yield x 100
Limiting reagent
Reactant not in excess which will be used up first and stop reaction.
Atom economy
A measure of how well atoms have been utilised.
Formula for atom economy
Sum of mrs of desired products/ sum of mrs of all products
What happens if you have high atom economy?
- Large proportion of desired products.
- Few waste products
- Important for sustainability- make most of resources
- Makes industrial processes more efficient, preserves raw material + reduces waste.
How do you work out particles?
Number of particles = n x NA
