Quantitative Analysis Flashcards
Define
empirical formula.
the formula showing the simplest whole number ratio of atoms of each element in a compound
Define
molecular formula.
the formula showing the actual number of atoms of each element in a molecule of a compound
Define
relative formula mass.
the sum of the relative atomic masses of all the atoms in a formula
What equation links
number of mol, mass and relative formula mass?
number of mol = mass / relative formula mass
n = m / Mr
What is the equation for
percentage mass?
percentage mass = (relative mass of element x 100) / relative formula mass
What equation links
number of mol with number of particles?
number of mol = number of particles / Avagadro’s number
n = N / NA
What is
Avagadro’s number?
6.02 x 10^23
What equation links
number of mols and volume?
(only gases)
number of mols = volume / molar gas volume
n = V / Vm
What is the
molar gas volume?
24
Define
atom economy.
the percentage of the mass of reactants that is converted into a desired product
How do you calculate
atom economy?
(mass of desired product x 100)
/
total mass of products from equation
Why don’t chemical reactions often have 100% yield?
- the reaction might be reversible (so there is a mixture of product and reactants)
- reactants might produce unexpected products (side reactions)
- some products might be lost in the experiment
- the reactants might not be pure
- products might be difficult to separate
Define
percentage yield.
the amount of product produced in a chemical reaction compared to the theoretical maximum amount of product as a percentage
How do you calculate
percentage yield?
(amount of product produced x 100) / theoretical amount of product
