C2 Revision prompts (each answer should take approximately 5 minutes)
-Explain in terms of electrons...
How a sodium atom becomes a sodium ion.

How an oxygen atom becomes an oxide ion.

How sodium and chlorine react to form sodium chloride.

-Describe the bonding in metals.

-Explain in terms of structure and bonding..
Why graphite can conduct electricity.

Why graphite is soft and slippery.

Why diamond is hard with a high melting point.

Why sodium chloride has a high melting point.

Why brass is harder than pure copper.

How a thermosoftening polymer can be recycled.

-Describe how gas chromatography can be used to separate compounds in a mixture.

-Describe how mass spectrometry can be used to identify compounds.

-What are the advantages of MS over titration methods of analysis?

-Describe how changing the...
-Temperature

-Pressure

-Concentration

...can affect the rate of a reaction.
-Describe...
-How Aluminium can be extracted by electrolysis.

-How Copper can be purified by electrolysis.

-The electrolysis of NaCl brine.

-Describe how to produce an insoluble salt from two soluble salts

-Describe how to produce a soluble salt from two soluble salts

Percentage mass(%)
Find the percentage by mass of:
a)
Lithium and oxygen in lithium oxide, Li2O.
b)
Carbon and hydrogen in ethane, C2H6.
c)
Sodium, hydrogen and oxygen in sodium hydroxide, NaOH.
d)
Sodium and chlorine in sodium chloride, NaCl.
Percentage yield
This is the amount of product produced (in grams) divided by the maximum
amount possible multiplied by 100 to produce a percentage.
a)
A reaction produces a theoretical yield of 200g but only makes 150g. What is the percentage
yield?
b)
A reaction produces 60g of product but in theory makes 80g. What is the percentage yield?
c)
How much of reactant A is needed to make 80g of product D if the percentage yield is 75%?
Empirical formula
From the mass of each element present in a sample we can find the formula of the compound.
1.
Sodium (2.3g) combine with oxygen (0.8g). How many moles of sodium and oxygen are there? How
many moles of sodium combine with 1 mole of oxygen? What is the formula of sodium oxide?
2.
Magnesium (0.27g) combine with nitrogen (0.28g). How many moles of magnesium and nitrogen are
there? How many moles of magnesium combine with 1 mole of nitrogen? What is the formula of
Magnesium nitride?
3.
Iron (1.68g) combine with oxygen (0.64g). How many moles of each element are there? How many
moles of Iron combine with 1 mole of oxygen? What is the formula for this Iron oxide?
4.
A compound contains 55.5% mercury; 44.5% bromine. How many grams of mercury and bromine
are there in 100g of the compound? How many moles of mercury and bromine are there in 100g of the
compound? What is the ratio of moles of bromine to moles of mercury. What is the formula?
Balancing equations
Remember that the number of atoms of each element on one side of the
arrow must equal the other side of the arrow. Don’t forget the state symbols…
1.
Na2O(s) + H2O(l)  NaOH(aq)
2.
KClO3(s)  KCl(s) + O2(g)
3.
Fe(s) + O2(g)  Fe2O3(s)
4.
Mg(s) + O2(g)  MgO(s)
5.
H2S(g) + O2(g)  H2O(g) + SO2(g)