quantitative chemistry (1) Flashcards
Moles=
moles = mass / mr
percentage mass of an element in a compound=
(mass of element) / (Mr of compound) x 100
Avogadro constant=
Avogadro constant= 6.02 x 10*23
explain the conservation of mass
in a reaction, mass is neither created nor destroyed so the mass of reactants= mass of products
can be lower or higher if the product or reactant is a gas which isn’t included in the initial/ final mass
how to balance equations using reacting masses
- calculate moles of each substance
- divide each number of moles by the smallest number of moles in the reaction
- if any numbers aren’t whole, multiply all numbers by the same amount until they are all whole
- write a balanced symbol equation
What is the limiting reactant?
how to find the mass of the product formed with limiting reactant
limiting reactant- the reactant used up first
- write balanced equation
- work out Mr of the reactant and product you want
- Find out how many moles there are of a known substance
- Work out moles of the other substance by the molar ratio
- use the number of moles to calculate the mass
volume of gas =
volume of gas= mass of gas/ mr of gas X 24
concentration=
concentration= moles / volume
how do you convert mol/dm3 to g/dm3
- work out mr of substance
- find mass by using the equation mass= moles X Mr
percentage Yield=
percentage Yield= actual yield/theoretical yield X 100
Atom economy=
Atom economy= mr of desired product/ mr of total reactants X 100
percentage abundance
(mass 1 x percentage 1) + (mass 2 x percentage 2) / 100
Titration calculation order
volume
concentration
moles
( x molar ratio)
Calculating reacting masses order
mass
mr
moles
( x molar ratio)
