4.4 Moles 1
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What is relative formula mass?
mass of a formula unit
What is the equation for RFM?
adding the relative atomic masses
What does percentage by mass show?
mass of an element in a substance
What is the equation for percentage by mass?
mass of element / RFM x 100
What is a mole?
unit of amount of a substance
What is the equation for moles?
moles = mass/RFM
What is mass measured in?
grams (g)
What is the empirical formula?
simplest mole ratio of elements in a substance
What is molecular formula?
actual number of atoms in a molecule
What is water of crystillisation?
crystals contain water trapped inside in a fixed mole ratio
What is the equation for water of crystillisation?
CuSO4 . 5H2O
What happens when salt crystals are heated?
lose their water
What is the hydrated copper sulphate broken down into when heated?
anhydrous copper sulphate and water vapour
What is the limiting substance?
not enough of substance for reaction
What is the excess substance?
too much of substance for reaction
What is the equation for percentage yield?
% yield = experimental / theoretical x 100
Where does the experimental value come from in percentage yield?
from experiment
Where does the theoretical value come from in percentage yield?
from calculation