AS OCR A Chemistry Core Questions

150 + core questions based on OCR A's AS spec for the new course. Topics 2.1.1, 2.1.2, 2.1.3, 2.1.4, 2.1.5, 2.2.1, 2.2.2, 3.1.1, 3.1.2, 3.1.3 and 4.1.4 covered.

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  • Created by: BethanyM
  • Created on: 17-01-16 19:50
Preview of AS OCR A Chemistry Core Questions

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AS Level Chemistry Core Qs 1
1 2.1.1 What are isotopes? Isotopes are atoms of the same element with
different numbers of neutrons and different
2 2.1.1 Define relative atomic mass RAM is the weighted mean mass of an atom
(Ar )
of the element relative to one twelfth the
mass of one atom of the C12 isotope, which
has a mass of exactly 12
3 2.1.1 Define relative isotopic mass The relative isotopic mass is the mass of an
atom of a particular isotope relative to one
twelfth the mass of one atom of the C12
isotope, which has a mass of exactly 12
4 2.1.1 How do you calculate relative
atomic mass? (% abundance x mass) + (% abundance x mass)
5 2.1.1 What are the two main uses (i) The determination of relative isotopic
of mass spectrometry? masses and relative abundances of the
(ii) Calculation of the relative atomic mass of
an element from the relative abundances of
its isotopes
6 2.1.1 How does the mass The mass spectrometer provides a trace that
spectrometer show this? shows the mass of each isotope and its
relative abundance .
7 2.1.1 What are the five stages, in 1) Vaporization
order, of mass spectrometry? 2) Ionisation
3) Acceleration
4) Deflection through a magnetic field
5) Detection
8 2.1.1 How are the particles Electrons are attracted to a positively
deflected in mass charged plate. They have a large deflection
spectrometry? because of their small mass. Neutrons do
not change path in a magnetic field. Protons
attracted to a negatively charged plate, but
their deflection is smaller because their mass
is larger.
9 2.1.1 What happens when an The organic compound loses an electron
organic compound is placed and forms a positive ion, called the
in the mass spectrometer? molecular ion.
10 2.1.1 What does the mass A mass spectrometer detects the
spectrometer detect? masstocharge ratio (m/z) of the molecular
ion, which gives the molecular mass of the

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How do you calculate a
masstocharge ratio? Relative mass of ion
Relative charge on ion
12 2.1.1 What relationship exists The time of flight of the sample (t) is
between the time of flight of proportional to the square root of the mass
the sample (t) and the mass (m) of the sample.
(m) of the sample?
13 2.1.3 What is the mole number in The mole contains the same number of
terms of the C12 isotope? particles as exactly 12 grams of carbon12.…read more

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What is the molecular The number and type of atoms of each
formula? element in a molecule.
23 2.1.3 If a salt is hydrated, what Water
does it contain?
24 2.1.3 If a salt is anhydrous, what Water
has been removed?
25 2.1.3 Define the term 'water of Water molecules form an essential part of
crystallisation' the crystal structure of the compound. %
water of crystallisation shows how much of
the hydrated salt is water.
26 2.1.…read more

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Multiply the empirical formula by the answer
to find the molecular formula.
35 2.1.3 What do ionic equations Ionic equations show only the reacting
show? particles (and the products they form.) Ions
that don't get involved in the reaction the
spectator ions aren't written.
36 2.1.2 What is the formula of the NO3
nitrate ion?
37 2.1.2 What is the formula of the CO3
carbonate ion?
38 2.1.2 What is the formula of the SO4
sulphate ion?
39 2.1.…read more

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What happens when strong For strong acids, nearly all of the acid will
acids are reacted with water? dissociate i n water, and lots of the H+ ions
Which arrow is used for the are released. As the equilibrium lies very far
reaction equation? to the right, a forward arrow is used.
50 2.1.…read more

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If you are completing a You need to double the number of moles of
titration calculation, what do a base to neutralise a diprotic acid.
you have to consider when
using a diprotic acid?
62 2.1.4 What is the molar volume
equation? Moles = concentration x vol (cm3)
63 2.1.3 How do you calculate
percentage yield? Percentage yield = Actual yield x100
Theoretical yield
64 2.1.3 Define 'atom economy.…read more

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The oxidation number of a Charge
monatomic ion is always the
same as its ________.
73 2.1.5 For molecular ions, the sum Overall charge
of the oxidation ions is
always equal to the ______
74 2.1.5 Oxygen nearly always has an 2
oxidation number of ____
(Exceptions: peroxides and
molecular oxygen.)
75 2.1.5 In peroxides, oxygen has an 1
oxidation number of ____.
76 2.1.5 Hydrogen usually has an +1
oxidation number of ____
(Exceptions: metal hydrides
and molecular hydrogen.)
77 2.1.…read more

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What is the relationship
between the quantum
number and the number of
electrons the shell can hold?
86 2.2.1 How many electrons can the 1st: 2
first four shells hold? 2nd: 8
3rd: 18
4th: 32
87 2.2.1 How do you define an atomic A region in space around the nucleus that
orbital? can hold up to two electrons with opposite
88 2.2.1 What is the shape of an s Spherical
89 2.2.…read more

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Do ionic compounds conduct Only when molten or in solution, as the
electricity? charged ions are free to move.
98 2.2.2 How is the ionic structure Ionic compounds have high melting and
linked to boiling point? boiling points. It takes a lot of energy to
overcome the strong electrostatic forces of
99 2.2.2 Are ionic substances soluble Most ionic compounds will dissolve in water,
in water? as water molecules are polar and are
attracted to the charged ions.…read more

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109 2.2.2 A molecule with two bonded Linear
pairs has a _____ shape.
The bond angle is _______.
110 2.2.2 A molecule with three Trigonal planar
bonded pairs has a _____
________ shape. The bond
angle is _______.
111 2.2.2 A molecule with four bonded Tetrahedral
pairs has a _____ shape.
The bond angle is _______.
112 2.2.2 A molecule with five bonded Trigonal bipyramidal
pairs has a _____ _______
/ 120o
shape. The bond angle is
113 2.2.…read more





hi VdbV how are you? :))

Sachin Patel27



AMAZING RESOURCE!!! Maybe add to the first definition 

the same number of protons because the spec has changed a bit and you have to say the same number of protons to get full mark

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