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Carre’s Grammar School
Chemistry Department
Year 11 Transition Day
Welcome to Chemistry.
We hope you enjoy your time with us today and can see that even though Chemistry is
challenging, it is also extremely rewarding. Carre’s Chemistry department is unique in terms
of its breadth of experience and knowledge base. We hope that in this course you will gain a
high level of knowledge and understanding of Chemistry enabling you to attain not only the
highest grades, but also a real appreciation of Chemistry in the wider context of the outside
world.
Expectations
The time allocation for this course is 10 hours over a two week cycle in year 12. In order to
be successful you are expected to do at least the same number of hours in terms of private
study.
Your progress will be monitored regularly and the first test will be within the first two to
three weeks of the course. Your progress will be continually assessed in terms of
assignments, tests, practical work and presentations. Take every assessment seriously – we
do!
Within the constraints of the time allocated, practical work will form a valuable aspect of this
course and students will develop a high level of practical skills. Practical skills are assessed
as part of the written exams at the end of the year, if students reach the required standard for
their practical work, they will receive a practical work endorsement on their A level
qualification. Practical work does not directly influence a student’s grade unlike coursework
at GCSE.
You are expected to know your work from GCSE; we will not have time to go over this
material.
Requirements for AS Chemistry
GCSE double award Science grade AA or GCSE Chemistry at grade B minimum, grade A or
above preferred. We expect students to have passed paper III Chemistry if sat.
The course has a significant mathematical content and AS Maths being studied is highly
recommended.
Grade A or above in Maths at GCSE level is very strongly advised; students with a lower
attainment level will need to concentrate considerable effort to ensure success.
All students will be expected to acquire and wear a laboratory coat (available for purchase
from the Chemistry Department) during all practical sessions.
AS / A2 Chemistry Specification
Exam Board: AQA Course Code: 7404 / 7405
These qualifications are linear. Linear means that students will sit all the AS exams at the end
of their AS course and all the A-level exams at the end of their A-level course.
Note,: the AS qualification does not count towards your grade at A2.
Subject content
3.1 Physical chemistry
3.1.1 Atomic structure
3.1.2 Amount of substance
3.1.3 Bonding
3.1.4 Energetics
3.1.5 Kinetics
3.1.6 Chemical equilibria, Le Chatelier’s principle and Kc
3.1.7 Oxidation, reduction and redox equations
3.1.8 Thermodynamics (A-level only)
3.1.9 Rate equations (A-level only)
3.1.10 Equilibrium constant Kp for homogeneous systems (A-level only)
3.1.11 Electrode potentials and electrochemical cells (A-level only)
3.1.12 Acids and bases (A-level only)
3.2 Inorganic chemistry
3.2.1 Periodicity
3.2.2 Group 2, the alkaline earth metals
3.2.3 Group 7(17), the halogens
3.2.4 Properties of Period 3 elements and their oxides (A-level only)
3.2.5 Transition metals (A-level only)
3.2.6 Reactions of ions in aqueous solution (A-level only)
3.3 Organic chemistry
3.3.1 Introduction to organic chemistry
3.3.2 Alkanes
3.3.3 Halogenoalkanes
3.3.4 Alkenes
3.3.5 Alcohols
3.3.6 Organic analysis
3.3.7 Optical isomerism (A-level only)
3.3.8 Aldehydes and ketones (A-level only)
3.3.9 Carboxylic acids and derivatives (A-level only)
3.3.10 Aromatic chemistry (A-level only)
3.3.11 Amines (A-level only)
3.3.12 Polymers (A-level only)
3.3.13 Amino acids, proteins and DNA (A-level only)
3.3.14 Organic synthesis (A-level only)
3.3.15 Nuclear magnetic resonance spectroscopy (A-level only)
3.3.16 Chromatography (A-level only)
Do I need chemistry to. . .
...study medicine?
An A-level (or equivalent) in chemistry is essential if you want to study medicine.
Surprisingly, biology is not required but maths and/or physics often are. Very good grades are
certainly needed and relevant work experience will significantly increase your chances of
gaining a place on a medicine degree course. Details of current requirements can be found on
the UCAS website.
...become a dentist?
Normally chemistry and biology at AS Level (or equivalent) are compulsory if you wish to
study dentistry. One or both of these subjects are also required at A Level (or equivalent).
Details of current course entry requirements can be found on the UCAS website.
...become a vet?
The qualifications needed to become a veterinary surgeon are similar to those for becoming a
doctor. Chemistry is required at A-level (or equivalent), along with A-levels in biology,
physics or mathematics. Current requirements can be found on the UCAS website.
...become a pharmacist?
Chemistry A-level is an entry requirement for many pharmacy courses, and is preferable for
all institutions.
Many people confuse pharmacy with pharmacology. Pharmacists are involved in the
dispensing of medicines and learn not only about the effects of different medicines and how
they interact, but also about regulations related to dispensing. Pharmacologists study the
effects of chemical compounds on humans and animals. They may work in clinical trials but
often work as part of a research team in a laboratory.
...become a materials scientist or metallurgist?
These careers are intimately involved with chemistry, physics, and engineering, so A-levels
(or equivalent) in chemistry, physics, engineering and mathematics are the best basis for
study in this area. Current entry requirements for courses can be found on the UCAS website.
Materials scientists can work in a very wide range of fields, from sports and aerospace
applications to medicine and communications. The Institute of Materials, Minerals and
Mining publishes helpful literature on both materials science and metallurgy.
AS Assessments
Paper 1
What's assessed
Relevant physical chemistry topics (sections 3.1.1 to 3.1.4, 3.1.6 and 3.1.7)
Inorganic chemistry (section 3.2)
Relevant practical skills
Assessed
written exam: 1 hour 30 minutes
80 marks
50% of the AS
Questions
65 marks of short and long answer questions
15 marks of multiple choice questions
Paper 2
What's assessed
Relevant physical chemistry topics (sections 3.1.2 to 3.1.6)
Organic chemistry (section 3.3)
Relevant practical skills
Assessed
written exam: 1 hour 30 minutes
80 marks
50% of the AS
Questions
65 marks of short and long answer questions
15 marks of multiple choice questions
A-level Assessments
Paper 1
What's assessed
Relevant physical chemistry topics (sections 3.1.1 to 3.1.4, 3.1.6 to 3.1.8 and 3.1.10 to
3.1.12)
Inorganic chemistry (section 3.2)
Relevant practical skills
Assessed
written exam: 2 hours
105 marks
35% of A-level
Questions
105 marks of short and long answer questions
Paper 2
What's assessed
Relevant physical chemistry topics (sections 3.1.2 to 3.1.6 and 3.1.9)
Organic chemistry (section 3.3)
Relevant practical skills
Assessed
written exam: 2 hours
105 marks
35% of A-level
Questions
105 marks of short and long answer questions
Paper 3
What's assessed
Any content
Any practical skills
Assessed
written exam: 2 hours
90 marks
30% of A-level
Questions
40 marks of questions on practical techniques and data analysis
20 marks of questions testing across the specification
30 marks of multiple choice questions
Kinetics – Practical.
Effect of Concentration on a Rate of Reaction
Sodium thiosulfate solution is reacted with acid – a sulfur precipitate forms. The time taken
for a certain amount of sulfur to form can be used to indicate the rate of the reaction.
Apparatus and chemicals
Eye protection
Each group will need:
250 cm3 Conical flask
100 cm3 Measuring cylinder
Sodium thiosulfate solution 50 g dm–3 (Low hazard)
Hydrochloric acid 2 mol dm–3 (Irritant)
Technical notes
Sodium thiosulfate solution 50 g dm–3 (Low hazard)
Dilute hydrochloric acid (Irritant at concentration used) Refer to CLEAPSS® Hazcard 47A
and Recipe Card 31
Student worksheet
Introduction
In this experiment, the effect of the concentration of sodium thiosulfate on the rate of reaction
is investigated.
What to record
1. Complete the table:
What to do
HEALTH & SAFETY
Wear eye protection. Take care not to inhale fumes.
Procedure
A. Put 50 cm3 of sodium thiosulfate solution in a flask.
B. Measure 5 cm3 of dilute hydrochloric acid in a small measuring cylinder.
C. Add the acid to the flask and immediately start the clock. Swirl the flask to mix the
solutions and place it on a piece of paper marked with a cross.
D. Look down at the cross from above. When the cross disappears stop the clock and note the
time. Record this in the table.
E. Repeat this using different concentrations of sodium thiosulfate solution. Make up 50 cm3
of each solution. Mix different volumes of the sodium thiosulfate solution with water as
shown in the table.
F. As soon as possible, pour the solution down the sink (in the fume cupboard if possible) and
wash away.
Questions
1. Calculate the concentration of sodium thiosulfate in the flask at the start of each
experiment. Record the results in the table.
2. For each set of results, calculate the value of 1/time. (This value can be taken as a measure
of the rate of reaction).
3. Plot a graph of 1/time taken on the vertical (y) axis and concentration on the horizontal (x)
axis.
4. Explain, using quantitative data, the relationship between concentration and rate of
reaction.
The Maxwell–Boltzmann distribution
Learning objectives
After completing the worksheet you should be able to:
interpret information provided in a graphical format
explain, using Maxwell–Boltzmann distributions, the effect of temperature, concentration and a catalyst on the rate of a reaction.
Introduction
A distribution curve is a map of occurrences between two variables. It is similar to a frequency histogram.
From a distribution curve it is possible to determine the most probable value (the mode) for a set of data. The shape of the curve provides information about the distribution of the variables within the sample. The area under the curve is an indication of the size of sample.
Questions
1 The diagram below shows the Maxwell-Maxwell–Boltzmann distribution of molecular energies in a sample of gas.
a Indicate on the graph:
i the most probable energy of the particles (1 mark)
ii an approximate position for the average energy of the particles.
(1 mark)
b Ea represents the activation energy that the particles need in order to react. Indicate on the graph, by shading, the number of particles with enough energy to react.
c A catalyst is added to the reaction. Indicate with Ecat a possible energy for the new activation energy for the reaction with the catalyst, and explain the effect of the catalyst on the rate of reaction. (3 marks)
2 The curve below shows the distribution of molecular energies in a gas at temperature, T1.
a Draw on the graph a second curve to represent the same sample of gas at a higher temperature. Label this curve T2. (2 marks)
b Explain any changes to:
iii the most probable energy of the particles (2 marks)
iv the total area under the curve (2 marks)
v the number of particles with the activation energy, Ea (2 marks)
vi the starting point of the curve (2 marks)
vii the end point of the curve. (2 marks)
c Draw on the graph what you would expect to see on the graph if you doubled the concentration of the reacting particles. (2 marks)
Summer Transition Work
Using online resources such as Kerboodle or text books solve the following problems.
Q1 A chemist reacted 0.243g of magnesium with chlorine to produce magnesium chloride.
Mg (s) + Cl2 (g) MgCl2 (s)
Calculate the amount, in mol, of magnesium that reacts.
Calculate the amount, in mol, of magnesium chloride that was made.
Calculate the mass, in grams, of magnesium chloride made. Give you answer to three decimal
places.
Q2 A student heated 2.50 g of calcium carbonate, which decomposed as shown in the
equation .
CaCO3 (s) CaO (s) + CO2 (g)
Calculate the amount, in mol, of calcium carbonate that decomposes.
Calculate the amount, in mol, of carbon dioxide that forms.
Calculate the volume in dm3, of carbon dioxide made.
Q3 A student reacted 4.00 g of calcium carbonate with 50 cm3 of hydrochloric acid. Calcium
chloride, water and carbon dioxide were produced in the reaction.
Write a balanced equation for this reaction.
Calculate the amount, in mol, of calcium carbonate that reacted.
Calculate the amount in mol, of hydrochloric acid that reacted.
Calculate the concentration of hydrochloric acid used.
Q4 A solution of sodium hydroxide contained 0.250 mol dm-3. Using phenolphthalein
indicator, titration of 25.0 cm3 of this solution required 22.5 cm3 of a hydrochloric acid
solution for complete neutralisation.
(a) write the equation for the titration reaction.
(b) what apparatus would you use to measure out
(i) the sodium hydroxide solution?
(ii) the hydrochloric acid solution?
(c) what would you rinse your apparatus out with before doing the titration ?
(d) what is the indicator colour change at the end-point?
(e) calculate the moles of sodium hydroxide neutralised.
(f) calculate the moles of hydrochloric acid neutralised.
(g) calculate the concentration of the hydrochloric acid in mol/dm3 (molarity).
Q5 A solution made from pure barium hydroxide contained 2.74 g in exactly 100 cm3 of
water. Using phenolphthalein indicator, titration of 20.0 cm3 of this solution required 18.7
cm3 of a hydrochloric acid solution for complete neutralisation. [atomic masses: Ba = 137, O
= 16, H = 1)
(a) write the equation for the titration reaction.
(b) calculate the molarity of the barium hydroxide solution.
(c) calculate the moles of barium hydroxide neutralised.
(d) calculate the moles of hydrochloric acid neutralised.
(e) calculate the molarity of the hydrochloric acid.
Q6 4.90g of pure sulphuric acid was dissolved in water, the resulting total volume was 200
cm3. 20.7 cm3 of this solution was found on titration, to completely neutralise 10.0 cm3 of a
sodium hydroxide solution. [atomic masses: S = 32, O = 16, H = 1)
(a) write the equation for the titration reaction.
(b) calculate the molarity of the sulphuric acid solution.
(c) calculate the moles of sulphuric acid neutralised.
(d) calculate the moles of sodium hydroxide neutralised.
(e) calculate the concentration of the sodium hydroxide in mol dm-3 (molarity).
Q7 100 cm3 of a magnesium hydroxide solution required 4.5 cm3 of sulphuric acid (of
concentration 0.100 mol dm-3) for complete neutralisation. [atomic masses: Mg = 24.3, O =
16, H = 1)
(a) give the equation for the neutralisation reaction.
(b) calculate the moles of sulphuric acid neutralised.
(c) calculate the moles of magnesium hydroxide neutralised.
(d) calculate the concentration of the magnesium hydroxide in mol dm-3 (molarity).
(e) calculate the concentration of the magnesium hydroxide in g cm-3.
Mathematical requirements
Arithmetic and numerical computation
Mathematical skills Exemplification of mathematical skill in the context of Chemistry
MS
0.0
Recognise and make use of
appropriate units in calculation
Students may be tested on their ability to:
Convert between units, e.g. cm3 to dm3 as part of volumetric
calculations
Give units for an equilibrium constant or a rate constant
Understand that different units are used in similar topic areas,
so that conversions may be necessary, e.g. entropy in J mol–1
K–1 and enthalpy changes in kJ mol–1.
MS
0.1
Recognise and use
expressions in decimal and
ordinary form
Students may be tested on their ability to:
Use an appropriate number of decimal places in calculations,
e.g. for pH
Carry out calculations using numbers in standard and ordinary
form, e.g. use of Avogadro’s number
Understand standard form when applied to areas such as (but
not limited to) Kw
Convert between numbers in standard and ordinary form
Understand that significant figures need retaining when making
conversions between standard and ordinary form, e.g. 0.0050
mol dm–3 is equivalent to 5.0 × 10–3 mol dm–3.
MS
0.2
Use ratios, fractions and
percentages
Students may be tested on their ability to:
Calculate percentage yields
Calculate the atom economy of a reaction
Construct and/or balance equations using ratios.
Mathematical skills Exemplification of mathematical skill in the context of Chemistry
MS
0.3
Estimate results
Students may be tested on their ability to:
Evaluate the effect of changing experimental parameters
on measurable values, e.g. how the value of Kc would
change with temperature given different specified
conditions.
MS
0.4
Use calculators to find and use
power, exponential and
logarithmic functions
Students may be tested on their ability to:
Carry out calculations using the Avogadro constant
Carry out pH and pKa calculations
Make appropriate mathematical approximations in buffer
calculations.
Handling data
Mathematical skills Exemplification of mathematical skill in the context of
Chemistry
MS
1.1
Use an appropriate number of significant
figures
Students may be tested on their ability to:
Report calculations to an appropriate number of
significant figures, given raw data quoted to varying
numbers of significant figures
Understand that calculated results can only be
reported to the limits of the least accurate
measurement.
MS
1.2
Find arithmetic means Students may be tested on their ability to:
Calculate weighted means, e.g. calculation of an
atomic mass based on supplied isotopic abundances
Select appropriate titration data (i.e. identification of
Mathematical skills Exemplification of mathematical skill in the context of
Chemistry
outliers) in order to calculate mean titres.
MS
1.3
Identify uncertainties in measurements and
use simple techniques to determine
uncertainty when data are combined
Students may be tested on their ability to:
Determine uncertainty when two burette readings are
used to calculate a titre value.
Algebra
Mathematical skills Exemplification of mathematical skill in the context
of Chemistry
MS
2.1
Understand and use the symbols: =, <, <<,
>>, >, , ~, equilibrium sign
No exemplification required.
MS
2.2
Change the subject of an equation Students may be tested on their ability to:
Carry out structured and unstructured mole
calculations, e.g. calculate a rate constant k from
a rate equation.
MS
2.3
Substitute numerical values into algebraic
equations using appropriate units for
physical quantities
Students may be tested on their ability to:
Carry out structured and unstructured mole
calculations
Carry out rate calculations
calculate the value of an equilibrium constant
Kc.
MS
2.4
Solve algebraic equations Students may be tested on their ability to:
Carry out Hess’s law calculations
Mathematical skills Exemplification of mathematical skill in the context
of Chemistry
Calculate a rate constant k from a rate equation.
MS
2.5
Use logarithms in relation to quantities
that range over several orders of
magnitude
Students may be tested on their ability to:
Carry out pH and pKa calculations.
Graphs
Mathematical skills Exemplification of mathematical skill in the context of
Chemistry
MS
3.1
Translate information between
graphical, numerical and algebraic
forms
Students may be tested on their ability to:
Interpret and analyse spectra
determine the order of a reaction from a graph
Derive a rate expression from a graph.
MS
3.2
Plot two variables from experimental or
other data
Students may be tested on their ability to:
Plot concentration–time graphs from collected or
supplied data and draw an appropriate best-fit curve.
MS
3.3
Determine the slope and intercept
of a linear graph
Students may be tested on their ability to:
Calculate the rate constant of a zero-order reaction
by determination of the gradient of a concentration–
time graph.
MS
3.4
Calculate rate of change from a
graph showing a linear relationship
Students may be tested on their ability to:
Calculate the rate constant of a zero-order reaction
by determination of the gradient of a concentration–
time graph.
Mathematical skills Exemplification of mathematical skill in the context of
Chemistry
MS
3.5
Draw and use the slope of a tangent
to a curve as a measure of rate of
change
Students may be tested on their ability to:
Determine the order of a reaction using the initial
rates method.
Geometry and trigonometry
Mathematical skills Exemplification of mathematical skill in the context of
Chemistry
MS
4.1
Use angles and shapes in regular 2D and
3D structures
Students may be tested on their ability to:
Predict/identify shapes of and bond angles in
molecules with and without a lone pair(s), for
example NH3, CH4, H2O etc.
MS
4.2
Visualise and represent 2D and 3D forms
including two-dimensional representations
of 3D objects
Students may be tested on their ability to:
Draw different forms of isomers
Identify chiral centres from a 2D or 3D
representation.
MS
4.3
Understand the symmetry of 2D and 3D
shapes
Students may be tested on their ability to:
Describe the types of stereoisomerism shown by
molecules/complexes
Identify chiral centres from a 2D or 3D
representation.