quantitative chemistry Flashcards
(12 cards)
how do you find relative formula mass
add together the relative atomic masses of all the atoms in that compounds molecular formula
what is avogadro’s constant
6.02 x 10^23
the number of particles in one mole of any substance
what is the equation for mole
the number of moles = mass/Mr
what is conservation of mass
in a chemical reaction mass is always conserved
- no atoms are created or destroy
- only bonds change
what is a chemical change
a rearrangement of the atoms in the reactant, to form the products
what does it mean for a reactant to be a ‘limiting reactant’
it all reacts and limits how much product can be formed
how do you find concentration (in grams per dm^3)
concentration = mass/volume
what is the equation for the volume of gas
volume of gas = moles x 24
what is the atom economy of a reaction
a measure of the proportion of starting materials that end up as useful products
what are the problems with low atom economy
- less sustainable as it will use more resources
- there will be more waste products
what factors should be considered when choosing between two different methods of producing a useful product
- percentage yield
- cost of raw material
- position of equilibrium
- rate of reaction
- cost of maintaining the right condition
- environmental impact of waste products
what are potential reasons as to why the percentage yield maybe be less than 100%
- the reactants may not all react
- there may be side reactions
- some of the products may be lost
