What is the correct equation for working out the percentage mass of an element in a compound?
(Relative formula mass x number of atoms of that element)/relative atomic mass of compound
(Relative atomic mass x number of atoms of that element)/relative formula mass of compound
(Relative atomic mass x relative formula mass of compoun)/number of atoms of that element
A mole is a system chemists use to count huge quantities of . It is given the symbol , and is measured in a unit called the mole, shorthand . A mole of any substance contains the same number of atoms that are contained in g of the isotope . One mole of a substance is simply the or expressed in
The reactant that gets used up first in a reaction is called the limiting reactant
Which of these do you need to work out the limiting reactant?
A balanced symbol equation
The relative formula mass
The number of moles of each reactant
The number of electrons
Percentage yield is the amount of a produce you as a you should
Why does a high percentage yield matter to people in the industry?
If a yield is know for a particular product you can work out how much reactant is needed
A higher percentage yield = less product to produce more = higher profit
It's easier to work out information
Raw materials are scarce and expensive and so must be carefully conserved
What is the correction equation for working out percentage yield?
Percentage yield = (Theoretical yield/actual yield) x 100
Percentage yield = (Number of atoms/theoretical yield) x 100
Percentage yield = (Actual yield/theoretical yield) x 100
Very few reactants have a percentage yield of 100% because:
Products may be left behind in the apparatus
It violates the law of conservation of mass
The reaction may not have completely finished
The raw minerals may not be pure
The atoms are destroyed in the reaction
Some reactants may give unexpected products
