Chemistry: 1. States of Matter
Syllabus
OC1 Name three states of matter and know their characteristics
Matter can exist in three states – solid, liquid and gas
Student Notes
Characteristics of Solids, Liquids and Gases
Solids
Liquids
Gases
Definite shape
No definite shape
No definite shape
Definite volume
Definite volume
No definite volume
Hard to compress
Hard to compress
Easy to compress
Do not flow
Flow easily
Diffuse to fill all available
space
Explanation
1. Every ‘thing’ is made up of very small particles (which we call ‘atoms’).
2. Atoms jiggle
These particles are so small that two million of them would fit into the full stop at the end of this sentence!
It’s not surprising that it took thousands of years before people believed that atoms exist. In fact many scientists,
including Einstein, were doubtful that atoms existed until just over 100 years ago.
We can now see atoms using special hi-tech microscopes.
These ‘atoms’ are always moving (jiggling), no matter how hot or cold the object is, and it is this movement that
determines whether the object is a solid, a liquid or a gas.
In a solid the atoms jiggle around a fixed position but don’t actually move anywhere. Now as you heat the solid the
atoms jiggle more quickly and push over and back over a greater area. So although you can’t see the atoms moving,
the solid itself actually expands slightly!
If you keep heating the solid then eventually the atoms get so much energy that they are able to leave their fixed
position and whole groups of atoms start to move off, sliding over each other while all the time continuing to jiggle.
We say that the solid is turning to a liquid.
If you keep heating the liquid even further then eventually the atoms get so much energy and vibrate so much that they
leave the rest of the liquid altogether and end up in the air. We say that the liquid is turning to a gas.
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Jiggling atoms and temperature
Can you explain why the level of alcohol in the thermometer rises when you dip a thermometer into a beaker of hot
water?
Answer
The atoms in the hot water are jiggling rapidly and bang off the atoms in the glass part of the thermometer. The glass
is solid so the atoms in the glass don’t move anywhere but because they are getting battered by the atoms in the water
outside they start to jiggle more rapidly. Some of these atoms are in contact with the alcohol so now these atoms start
to jiggle more rapidly and as a result the alcohol rises a little on top due to all this movement.
So what a thermometer is actually responding to the jiggliness of the atoms – the more the atoms jiggle the higher the
thermometer reading!
Evaporation and Boiling Point
At room temperature some of the atoms in water get enough energy to leave the liquid and become part of the air. This
happens slowly and we call this evaporation.
However at a certain temperature (100 0C) every atom can leave the liquid and when this starts to happen we say that
the water is boiling.
Condensation is the changing of a gas to a liquid e.g. steam meeting cold glass.
Sublimation is the changing of a solid directly to a gas on heating e.g. iodine, dry ice, volcano sulfur.
Exam Questions
1. [2006 OL]
The diagrams on the right show the arrangement of particles in a solid, a
liquid and a gas.
(i) Which diagram A, B or C shows a gas?
(ii) Name the physical change that takes place when A changes into B.
2. [2007 OL]
The three states of matter are solid, liquid and gas.
The diagram shows the arrangement of particles in the three states of matter.
(i) In the table write the letter S beside the arrangement of particles in a solid.
(ii) Write the letter G beside the arrangement of particles in a gas.
3. [2006]
Study the diagram carefully. It shows the ways that the particles of gases and solids occupy space.
The particles of gas have lots of space and move randomly at high speeds in three dimensions and collide with
each other and with their container.
The arrows represent the velocities of the gas particles.
The particles of a solid are packed closely together and cannot move around
but they can vibrate.
Give one property of a gas and one property of a solid that you have
observed and is consistent with (matches) this micro-view of these states of
matter.
4. [2009]
There are three states of matter: solid, liquid and gas.
(i) Give one property that liquids and gases have in common.
(ii) Give one property in which liquids and gases differ.
5. [2009 OL]
The three states of matter are solid, liquid and gas.
The diagram shows the arrangement of particles in the three states of matter.
(i) In the table write the letter L beside the arrangement of particles in a liquid.
(ii) Write the letter G beside the arrangement of particles in a gas.
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3
OC3
OC4
Chemistry: 2. Elements, Compounds and Mixtures
Syllabus
Understand what an element is and recall that all known elements are listed in the Periodic Table; understand
what a compound is and what a mixture is; recall that when elements combine to form compounds they may
lose their individual properties
Examine a variety of substances and classify these as elements or compounds (using the Periodic Table as a
reference)
OC12 Compare the properties of the simple compounds H2O, CO2, MgO and FeS to those of the constituent
elements
OC13 Compare mixtures and compounds made from the same constituents, and understand that an alloy is a mixture
OC41 Understand how atoms of elements combine to form compounds
Student Notes
We saw in the last chapter (States of Matter) that everything is made of atoms.
It turns out that there are many different types of atom (over 100 in fact), and some substances are made from just one
type of atom, while other substances are made from combinations of different types of atom.
Elements
The different types of atom are arranged in terms of their size in a table called the Periodic Table of elements.
Elements are substances which are made up of only one type of atom
Molecules
Some atoms form a very strong attachment (‘bond’) to another atom or atoms and as a result they always go around in
groups of two or more atoms. We call these guys ‘molecules’.
It is very hard to break these ‘bonds’ and we say that in this case the atoms are ‘chemically combined’. We will look
at this bonding in detail in another chapter later.
A molecule is made up of two or more atoms chemically combined
Basically a molecule is like a very small group of atoms that go around together (they are still too small to see).
Hydrogen usually goes around in pairs of hydrogen atoms, so we say that H2 is a hydrogen molecule.
A water molecule is made up of one atom of oxygen together with two atoms of hydrogen; that’s why it has the
symbol H2O.
Compounds
Compounds are substances made from two or more different types of atom chemically combined
My head hurts; what’s the difference between a compound and a molecule?
All compounds are molecules, but not all molecules are compounds (e.g. H2 is a molecule because it is composed of
two atoms chemically combined, but because they are both hydrogen atoms the molecule is not a compound).
Remember when we said that atoms are so small that you can’t see them? Well molecules are made up of small groups
of atoms so you won’t be able to see them either.
A compound however might be something like table-salt; you can hold it in your hand. It is a compound because it is
made up of two different types of atom – in this case sodium and chlorine. The chemical name for table-salt is NaCl.
The interesting thing is that both sodium and chlorine can be fatal if ingested (swallowed) but when the two go
together to form table salt the result is perfectly safe (once you don’t eat too much!).
We can summarise this as follows:
When elements combine to form compounds they may lose their individual properties.
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Mixtures
If a substance is made up of different components but they are just mingled together rather than combined at an atomic
level then we call this a mixture.
A mixture contains two or more different substances mingled together but not chemically combined
I don’t know what needs to be learnt for the rest of this chapter !!!!!
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Exam Questions
1. [2006 OL]
Complete the table below identifying one mixture and one compound from the list on the
right.
MIXTURE COMPOUND
2. [2009 OL]
Complete the following sentence using the words from the list on the right.
Water is an example of a _______________ and hydrogen is an ________________ found in
water.
Table Salt
Carbon
Air
Element
Compound
3. [2007 OL]
Write the name of each of the two elements present in water.
4. [2009 OL]
In each case write the symbol of the metallic element beside its name in the table on the
right.
Aluminium
Copper
5. [2007]
Marie Curie showed the existence of the element radium and she produced 0.1 g of the compound radium chloride
in 1902 by processing tons of pitchblende ore obtained from mines in Bohemia.
Explain the underlined terms.
Other Test Questions
1. What is an element?
2. What is a compound?
3. Give four examples of compounds.
4. What is a molecule?
5. What is a mixture?
6. Explain the difference between a physical change and a chemical change in chemistry:
Physical:
Chemical:
7. Give one example of a physical change and a chemical change that you have observed
Physical:
Chemical:
8. A student carried out an investigation comparing the properties of a mixture of iron and sulphur and the compound
iron sulphide.
Name and explain a method that the student could use to separate the iron from the sulphur in the iron and sulphur
mixture.
Method of separation:
Explanation:
Could the method of separation that you have suggested be used to separate the iron from the sulphur in the
compound iron sulphide?
Explain your answer.
9. Which two of the following five examples represent a chemical change?
(i) Rusting of iron
(ii) Melting of ice
(iii) Burning of gas
(iv) Grinding of coffee beans
(v) Magnetising of steel
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OC2
Chemistry: 3. Separating Mixtures
Syllabus
Separate mixtures using a variety of techniques: filtration, evaporation, distillation and paper chromatography
OC32 Carry out a simple distillation, and obtain a sample of water from sea-water
Student Notes
A mixture is made up of two or more substances mingled together but not chemically combined
Filtration is a way of separating a liquid and an in soluble liquid
e.g. soil and water.
Use filter paper, filter funnel and conical flask.
Evaporation is used to separate a soluble solid and a liquid
The problem is that it loses the solvent. e .g. water and salt.
By boiling the mixture the solvent e.g. water, will evaporate and will leave you with the solute.
Distillation can be used to separate two miscible liquids with
different boiling points (and you get to keep both)
Distillation can be used to separate a soluble solid and a liquid
(and you get to keep both)
A: Thermometer
B: Water out to sink
C: Condenser
D: Cold water in
E: Tripod stand
F: Bunsen
Chromatography is used to separate a mixture of dies in an ink
Put an ink spot just above the water line as shown.
Water rises up through the chromatography paper and takes the various colours which
were in the ink spot to different heights.
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To obtain a sample of water from sea-water using simple distillation
1. Set up as shown
Part A is called a liebig condenser; an outer tube used to cause the water vapour to
condense. Cold water goes in through Y and out through X.
2. Flask A contains sea-water
3. The water evaporates from flask A, travels through the condenser where it
condenses and flows into flask B as pure water.
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Exam Questions
1. [2006]
How would you show that water contains dissolved solids?
2. [2008 OL]
Describe, with the aid of a labelled diagram, how you could carry out an experiment to separate soil from a
mixture of soil and water.
Use the headings below.
Labelled diagram, Equipment, Procedure, Result
3. [2007 OL]
(i) What is the name given to the separation technique shown in diagram?
(ii) Name two substances which could be separated using this technique.
4. [2009]
Draw a labelled diagram of an apparatus that could be used to separate an
insoluble solid from a liquid.
5. [2006 OL]
Separation techniques are very important in chemistry.
(i) What is the name given to the separation technique shown in the diagram?
(ii) Name two substances which could be separated using this technique?
(iii) Name the part of the apparatus labelled X in the diagram.
(iv) What is the name given to the separation technique shown in the second
diagram on the far right?
6. [2008 OL]
Separation techniques are very important in chemistry.
(i) What is the name given to the separation technique shown in the diagram?
(ii) Name two substances which could be separated using this technique.
7. [2007]
The apparatus shown in the diagram can be used to separate mixtures.
(i) Name part A.
(ii) Which connection, X or Y, is attached to the cold tap?
(iii) Flask A contains seawater. Name the liquid that collects in flask B.
(iv) Name a constituent of seawater that does not move from flask A to flask B.
8. [2009]
(i) Name the separation process shown in the diagram.
(ii) Name the item labelled C in the diagram.
(iii) Identify the part A or B of item C which is connected to the cold tap.
(iv) How could you show that the water collected contains no salt?
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9. [2009 OL]
Separation techniques are very important in chemistry.
The apparatus in the diagram below was used to
separate a mixture of water and a dissolved dye. Study
the diagram.
(i) Complete the table correctly matching the labels A – F
in the diagram with words/phrases in the table.
(ii) What is the name given to the separation technique
shown in the diagram above?
(iii) A colourless liquid was collected in container E during
the separation. Name a substance you could use to show
that this liquid was water.
(iv) What colour change is observed in this test to show that
water is present?
10. [2007 OL]
Separation techniques are very important in chemistry.
The apparatus in the diagram was used to separate sea-water.
Study the diagram.
(i) Complete the table correctly matching the labels A – F in the
diagram with words/phrases in the table.
(ii) What is the name given to the separation technique shown in the
diagram?
11. [2008 OL]
A solution of dye can be separated into its constituent colours using the method shown in the
diagram.
(i) Identify a liquid X that can be used in this separation.
(ii) What name is given to this type of separation?
12. [2008]
(i) Describe an experiment, using a labelled diagram in the box provided, to investigate the composition of inks in
markers containing water-soluble inks, to see if they are a single-colour ink or a mixture of coloured inks.
(ii) On completion of the experiment how is it possible to distinguish between a marker containing a pure singlecolour ink and a marker containing mixture of coloured inks.
13. [2006]
A spot of water-soluble ink was put on a piece of chromatography paper and set up
as shown in the diagram. The ink used was a mixture of different coloured dyes.
(i) What happens to the ink spot as the water moves up the paper?
(ii) What would happen to a spot of water-soluble ink consisting of a single coloured
dye if it were used in the above experiment?
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Separating Mixtures
10. Describe briefly with the aid of a diagram how to separate salt from water.
11. Describe briefly with the aid of a diagram how to separate alcohol from water by distillation.
12. Describe briefly with the aid of a diagram how to separate a mixture of inks using paper
chromatography.
13. How does filtration work?
14. How does crystallisation work?
15. A student attempts to separate water from a salt water solution using the apparatus
shown.
(i) What’s left in the round bottomed flask at the end of the experiment?
(ii) Name the part labelled X and explain how it functions.
(iii) Name the method of separation shown in the diagram.
(iv) Identify a mixture that could be separated by using this method.
(v) How does the design of X enable it to carry out its job?
16.
(i) The ink in a biro is an example of a mixture. Explain what is meant by a mixture.
(ii) What technique, in a laboratory, could be used to separate the mixture of pigments in
biro ink?
17.
(i) Name the piece of apparatus shown in the diagram.
(ii) Name the separation technique that uses this piece of apparatus.
18. Alcohol and water can be separated by distillation.
(i) What is the difference between the two liquids that allows them to be separated by this technique?
(ii) Which liquid is the distillate?
19.
(i) Give two safety precautions when heating a substance in a test tube.
(ii) Name a solvent and a solute that would dissolve in it.
20. Name a substance, other than water, that forms crystals.
Give one difference between crystalline and non-crystalline solids.
21. Give two methods that a student could use to make dilute copper sulphate solution more concentrated when
making copper sulphate crystals.
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Chemistry: 4.The Atom
Syllabus
OC39 Describe the structure of the atom, state the location, relative charge, and atomic mass of the sub-atomic
particles, and define atomic number and isotope
OC40 Draw the Bohr structure of the first 20 elements
Student Notes
An atom is the smallest particle of an element which still retains the properties of that element
In other words, an atom of iron is the smallest piece of iron that shows all of the properties of copper.
Structure of the atom
The atom has a solid central section called the nucleus with particles in orbit around it.
The tiny particles found inside the atom are called “sub-atomic particles”.
There are three particles; protons, neutrons and electrons
The electrons revolve around the nucleus of an atom in fixed paths called orbits (shells) to form an electron cloud.
Particle
Proton
Neutron
Electron
Location
Inside the nucleus
Inside the nucleus
Outside the nucleus
Mass
1 Unit
1 Unit
2000 times smaller than
the mass of a proton
Charge
+1
0
-1
All atoms are neutral. Therefore, the number of protons must equal the number
of electrons.
Atomic number
The atomic number is the number of protons in an atom
Mass number
The mass number is the number of protons plus neutrons in an atom
This means that the number of neutrons = mass number – atomic number
Example
The atomic number of fluorine is 9 and its mass number is 19.
How many (i) protons, (ii) electrons and (iii) neutrons does a neutral fluorine atom have?
(i) 9 protons, (ii) 9 electrons (same number as the number of protons), (iii) 10 neutrons (19 – 9)
Isotopes
Scientists used to think that all atoms of a given element were identical, but then they discovered some elements have
two or even three different types of atom. They will all have the same number of protons (e.g. all sodium atoms have
11 protons, all atoms of carbon have 6 protons), but they could have a different number of neutrons.
e.g. some atoms of carbon have 6 neutrons, while other atoms of carbon have 8 neutrons.
We say these atoms are isotopes of each other.
Isotopes are atoms which have the same atomic number but different mass number
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These are the first 10 elements:
Hydrogen Helium
Element
H
He
Symbol
1
2
Atomic no.
Lithium
Li
3
Beryllium
Be
4
Boron
B
5
Carbon
C
6
Nitrogen
N
7
Oxygen
O
8
Fluorine
F
9
Neon
N
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The Periodic Table
The Periodic Table is an arrangement of elements in order of increasing atomic number
The periodic table contains over 100 different elements.
The elements are arranged in a certain way in the periodic table.
All the atoms in the first column have one electron in their outer shell, all electrons in the second column have two
electrons in their outer shell and so on.
A Bohr diagram
This way of understanding the atom was proposed by the Danish scientist Neils Bohr over 100 years ago, and so these
diagrams are known as Bohr diagrams.
While all the protons and neutrons are packed tightly together in the central nucleus, the electrons are arranged in a
very specific pattern, according to a set of rules.
1. Only two electrons can be in the first orbital (shell).
2. Up to 8 electrons can be in all the other shells.
3. The inner shells must get filled up before electrons appear in an outer shell.
Example: Argon
Argon has an atomic number of 18.
This means that it has 18 protons and also 18 electrons.
So 2 electrons go in the first shell (represented by black dots).
8 electrons go in the next shell.
8 electrons go in the outside shell.
We call the arrangement of electrons the electronic
configuration:
e.g. the electronic configuration of argon is 2,8,8
Calcium has an atomic number of 20, so the electronic
configuration of calcium is 2,8,8,2
The next 10 elements:
Element
Symbol
Atomic no.
Sodium Magnesium Aluminium Silicon Phosphorus Sulphur Chlorine Argon
Na
Mg
Al
Si
P
S
Cl
Ar
11
12
13
14
15
16
17
18
14
Potassium
K
19
Calcium
Ca
20
Exam Questions
1. [2006 OL]
Complete the statements below using one of the words from the list on the right in each case.
(i) Protons are ________________ charged particles.
(ii) Electrons are ________________ charged particles.
Negatively
Positively
2. [2007 OL]
The sentences below have words omitted.
Complete the table on the right correctly matching the numbers 1 – 3 with the words in the
table.
(i) Neutrons and ____1_____ are located in the nucleus of atoms.
(ii) The ____2_____ move around outside the nucleus of atoms.
(iii) The ____3_____ have no electric charge.
3. [2008 OL]
Atoms are composed of smaller particles.
Choose the correct particle from the list on the right to complete each statement below.
(i) The ___________________ is a particle that has no electric charge.
(ii) The ___________________ is a particle that has a positive charge.
(iii) The ___________________ is a particle located outside the nucleus.
(iv) The ___________________ is a particle that has a relative atomic mass of one unit.
Electrons
Neutrons
Protons
Proton
Neutron
Electron
4. [2009 OL]
Atoms are composed of tiny particles.
Choose the correct particles from the list on the right to complete each statement below.
(i) The particles located outside the nucleus are the ________________.
Protons
(ii) The particles that have no electric charge are the ________________.
Electrons
(iii) The particles that have a positive charge are the _________________.
Neutrons
(iv) The particles lost, gained or shared when atoms form bonds are the ________________.
(v) Different types of bond can be formed when atoms combine.
(vi) What name is given to the bond that involves an attraction between positive and negative ions?
5. [2008]
Sir Joseph John Thomson (1856-1940) announced his discovery of the electron in 1897 following extensive
experimental work. He was awarded the Nobel Prize in 1906. Compare the charge and the mass of an electron
with the charge and the mass of a proton.
6. [2007]
The diagram represents a sodium atom.
The circles are electron orbits and the ‘Na’ represents the nucleus. The atomic number of
sodium is 11.
Using dots or Xs to represent electrons in the orbits give the electronic structure of sodium.
7. [2006]
Niels Bohr received the Nobel Prize for physics in 1922 for his model of the
electronic structure of the atom. Potassium has an atomic number of 19.
Give the arrangement of the electrons in an atom of potassium.
8. [2009]
Approximately 98.89% of carbon on the surface of the earth and in the atmosphere is carbon-12. The remaining
approximately 1.11% is carbon-13. The numbers 12 and 13 are mass numbers. The atomic number of carbon is 6.
(i) How many neutrons are in the nucleus of a carbon-13 atom?
(ii) Enter the missing word in the following sentence.
Carbon-12 and carbon-13 are _________________________ of carbon.
9. [2008]
Define atomic number.
10. [2006][2008]
Define the term ‘isotope’.
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Other Test Questions
1. Describe the structure of the atom.
2. Give the location, relative charge, and atomic mass of the sub-atomic particles by filling in the following table:
Name of particle
Proton
Neutron
Electron
Position in the atom
Proton
Relative charge
Atomic mass
1unit
-1
3. Define the term isotope.
4. Why are atoms neutral in charge?
5. For each of the following elements give the atomic number, mass number and the number of electrons: Hydrogen,
Carbon, Neon and Calcium (you may make use of log tables).
6. Draw the Bohr structure of the following elements: Hydrogen, Carbon, Neon, Calcium (you may make use of log
tables).
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12
7. What is the difference between atoms of these two carbon isotopes:
C
C
6
6
8. Define the term atomic number.
9. Define the term mass number.
10. How many protons and neutrons are in an atom of fluorine?
9
F
19
11. Calcium has an atomic number of 20. Give the arrangement of electrons in an atom of Calcium.
12. Draw the arrangement of electrons in an atom of the element Magnesium.
16
12
Mg
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