Chemistry HL
IB Exam Review
Graphs You Should Know/Be Able to Use for Chemistry HL
Topic 1 – Quantitative Chemistry
1.4.8
Analyze graphs relating to the ideal gas equations.
Use the Ideal Gas Law to help you.
PV = nRT
Rearrange the equation to give:
R = PV/nT
Each of these graphs shows the relationship between TWO variables when the others are
constant.
P
P
P
V
1/V
V
T
V
T
n
Topics 2/12 – Atomic Structure
12.1.2 Explain how successive ionization energy data is related to the electron configuration of an atom.
a) Identify, with a reason, the element in each successive ionization energy graph.
b) Explain how this data supports the existence of energy levels in atoms.
Topics 3/13 – Periodicity
3.2.2
Describe and explain the trends in atomic radii, ionic radii, first ionization energies,
electronegativities and melting points for the alkali metals and the halogens.
3.2.3
Describe and explain the trend in atomic radii, ionic radii, first ionization energies,
electronegativities and melting points for elements across Period 3.
Chemistry HL
1. Atomic radius vs atomic number
• trend across a Period = ?
• trend down a Group = ?
2. First ionization energy vs atomic number
• trend across a Period = ?
• trend down a Group = ?
• anomolies between Be and B,
N and O, Mg and Al, P and S = ?
3. Electronegativty vs atomic number
• trend across a Period = ?
• trend down a Group = ?
4. Melting point vs atomic number
• trend across a Period = ?
• trend down a Group = ?
Remember that melting
and boiling points are explained
by the strength of the intermolecular
forces of attraction.
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Chemistry HL
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Topics 4/14 – Bonding
4.5.1
Compare and explain the properties of substances resulting from different types of bonding.
Include melting and boiling points, volatility, electrical conductivity and solubility in polar and
non-polar solvents.
Any graph that shows the effect of bond type, type of intermolecular forces or strength of
intermolecular forces could be fair game!
1. Effect of Chain Length on the Melting Point of Alkanes
• Remember to consider the role of intermolecular
forces whenever you explain melting point or
boiling point.
2. Boiling Point of Group 4, 5, 6 and 7 Hydrides
• Explain the trends observed in
the boiling point of the hydrides
(i.e. compounds containing hydrogen
plus another element) in each Group.
• Note in Group 4 hydrides, BP increases
as you go down the group. This is
due to an increase in molar mass and
thus stronger van der Waals forces.
• In Groups 5, 6 and 7, the smallest hydride
has an unusually high BP. This is due to
the hydrogen bonding present in NH3, H2O
and HF. Hydrogen bonds are stronger than
van der Waals forces.
Chemistry HL
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Topics 5/15 – Energetics
5.1.4
5.2.3
Deduce, from an enthalpy level diagram, the relative stabilities of the reactants and products and
the sign of the enthalpy change.
exothermic reaction
endothermic reaction
products more stable than reactants
reactants more stable than products
negative ∆H
positive ∆H
bonds in products stronger than reactants
bonds in reactants stronger than products
more energy released when bonds form
in products than used to break bonds in
reactants
more energy used to break bonds in
reactants than released when bonds form
in products
Calculate the enthalpy change for a reaction using experimental data on temperature changes,
quantities of reactants and mass of water.
e.g.
Determine final temperature values from calorimetry data for slow reactions.
Extrapolate the line backwards to the time the reaction was initiated.
final temp = 72.0ºC
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Topics 6/16 – Kinetics
6.1.3
Analyse data from rate experiments.
Students should be familiar with graphs of changes in concentration, volume and mass against time.
1. change in REACTANTS versus time
• know general shape
• know effects of conditions on rate
(i.e. slope)
• know effect of limiting reactant
2. change in PRODUCTS versus time
• know general shape
• know effects of conditions on rate (i.e. slope)
• know effect of limiting reactant
(e.g. original and II versus I)
……
Answer questions from PE diagrams/enthalpy diagrams
• identify Ea, ∆H and
the transition state/
activated complex
6.2.5
Sketch and explain qualitatively the Maxwell–Boltzmann energy distribution curve for a fixed
amount of gas at different temperatures and its consequences for changes in reaction rate.
Students should be able to explain why the area under the curve is constant and does not change with temperature.
T1 < T2
• This graph shows the same
reaction (same Ea) at two different
temperatures.
• Refer to the area under the curve in
your explanations.
6.2.7
Sketch and explain Maxwell–Boltzmann curves for reactions with and without catalysts.
Chemistry HL
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• This graph shows a reaction at ONE
temperature, with and without a catalyst.
• Refer to the area under the curve in
your explanations.
16.1.4 Sketch, identify and analyse graphical representations for zero-, first- and second-order reactions.
Students should be familiar with both concentration–time and rate–concentration graphs.
16.3.2 Determine activation energy (Ea) values from the Arrhenius equation by a graphical method.
• Remember the Arrhenius equation
is in Table 1 of the Data Booklet.
• Remember T is in Kelvin degrees.
Topics 7/17 – Equilibrium
7.1.1
Outline the characteristics of chemical and physical systems in a state of equilibrium.
You should be able to sketch or interpret graphs of systems at equilibrium.
• concentration vs time
P
R
K>1
products favoured
R
P
K<1
reactants favoured
Chemistry HL
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• rate vs time
17.1.2 Sketch graphs showing the relationship between vapour pressure and temperature and explain
them in terms of the kinetic theory.
weaker IMF
more volatile
higher VP @ a given T
lower BP

stonger IMF
less volatile
lower VP@ a given T
higher BP
1. Compare curves for substances
with different intermolecular
forces.
2. Find the boiling point.
BP of ethanol at
atmospheric pressure
(101.3 kPa) = 79ºC
Topics 8/18 – Acids and Bases
18.4.1 Sketch the general shapes of graphs of pH against volume for titrations involving strong and
weak acids and bases, and explain their important features.
Only examples involving the transfer of one proton will be assessed. Important features include intercept with pH axis;
equivalence point; buffer region and points where pKa = pH or pKb = pOH.
1. Find values from a
titration curve.
Chemistry HL
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half equivalence
point: V = 12.5 mL
volume to reach
equivalence = 25 mL
2. Recognize titration curve shapes for different acid/base combinations.
Identify the analyte and titrant.
Use the pH at the equivalence point to determine the nature of the salt produced (neutral,
acidic or basic).
a) acid analyte + base titrant
b) base analyte + acid titrant
c) select the best indicator for a titration
Chemistry HL
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Topics 9/19 –Oxidation and Reduction
NO GRAPHS are mentioned in the assessment statements. 
Topics 10/20 –Organic Chemistry
See graphs for Topics 4/14 on bonding and the effect of intermolecular forces on boiling and melting point.
See graphs for Topics 7/17 on vapour pressure and the nature of the compound.
Option D – Medicines and Drugs
D.1.4
Discuss the terms therapeutic window, tolerance and side-effects.
LD50
ED50
Option E – Environmental Chemistry
E.3.1
Describe the greenhouse effect.
A classic!
Can you explain the annual cycle?
E.9.3
Outline the reasons for greater ozone depletion in polar regions.
Consider the seasonal variation in temperature in the upper atmosphere. Refer to surface catalysis on ice particles.
Chemistry HL
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Watch out for the type of season and the
hemisphere!
Ozone depletion is greatest in the spring,
and decreases in the summer.
E.10.2 Outline the formation of secondary pollutants in photochemical smog.
Examples include NO2, O3, aldehydes and peroxyacylnitrates (PANs). The role of free radicals and sunlight should be
emphasized.
Distinguish between the timing
of primary pollutants (NO and VOCs) and
secondary pollutants (NO2).
Also consider the timing of the
photochemical reaction products
(which require sunlight).
E.5.4
Describe the source and effects of thermal pollution in water.
E.5.3
Describe the process of eutrophication and its effects.
This graph shows the effects on
dissolvd oxygen and BOD at
various distances from the point
of discharge of organic pollutants
or nitrates into a river.
Chemistry HL
IB Exam Review