EDEXCEL IGCSE CHEMISTRY EXAM
EDEXCEL IGCSE CHEMISTRY EXAM
QUESTIONS AND ANSWERS GRADED A+
Experiment for Diffusion? - correct answer 1) HCl placed at one end
of the test tube, ammonia solution at the other.
2) Where they meet, a ring of Ammonium Chloride appears.
3) The diagram shows that the ammonia is closer to the ring,
showing that ammonia must have travelled faster, showing it's a
lighter gas.
Experiment for Dilution? - correct answer 1) Put a coloured
substance in a solvent e.g. food colouring in water.
2) Over the time, the colour levels out but is weaker than the
original solution- Dilution
3) More heat = more kinetic energy = happens faster, rate of
dilution quicker.
,EDEXCEL IGCSE CHEMISTRY EXAM
What is filtration? - correct answer Making a barrier which one
component of a mixture can pass through but the other is
caught by.
What is distillation? - correct answer When one substance is
evaporated off while the other remains.
What is fractional distillation? - correct answer A mixture is
evaporated and rises up a tube. Different substances have
different boiling points and so will condense at different
temperatures. As the mixture travels up the tube, the
temperature decreases, substances are collected at different
places. Separates a mixture into its different parts.
What is crystallisation? - correct answer A solution is warmed,
allowing the solvent to evaporate; the solution is now left to
cool and will form crystals.
What is chromatography? - correct answer Chromatography paper
is placed in a substance; the different components of the
substance will travel at different speeds due to the size of the
particles.
,EDEXCEL IGCSE CHEMISTRY EXAM
How can information from chromatograms be used to identify
the composition of a mixture? - correct answer Chromatography
paper is placed in a solvent- the different compounds will travel
at different speeds due to the size of their particles.
What is the atomic number? - correct answer Number of protons
(same as the number of electrons)
What is the atomic mass number? - correct answer Number of
neutrons & protons together
What are isotopes? - correct answer Atoms of an element with the
same number of protons but a different number of neutrons
What is the RAM (relative atomic mass)? - correct answer the mass
of one atom of an element in relation to Carbon
How do you work out the relative formula mass (Mr) from the
relative atomic mass (RAM)? - correct answer (Number of that
element in a molecule x its RAM) + (Number of other elements
in a molecule x its RAM)
, EDEXCEL IGCSE CHEMISTRY EXAM
Triangle for carrying out equations using AR & Mr - correct answer
Moles (mol) = Mass (g) / RFM (Mr)
How do you work out moles for a gas? - correct answer Moles =
Mass (g) / 24,000 cm3 (24dm3)
Difference between a liquid (l) and an aqueous solution? - correct
answer an aqueous solution is a solid dissolved in a liquid.
How can you obtain the formula of a simple compound
experimentally? - correct answer 1) Weigh your compound of two
elements.
2) Remove an element through a reaction. Weigh again. This
gives you the individual mass of both elements in the
compound.
3) Work out the formulae by dividing the weight by its Ar.
egg 22g with an AR of 11 = 22/11 = 2
How to work out the empirical formula? - correct answer 1) Find
the masses of each element in a compound by taking each
element out and weighing.
2) Turn these masses into percentages of the compound.
EDEXCEL IGCSE CHEMISTRY EXAM
QUESTIONS AND ANSWERS GRADED A+
Experiment for Diffusion? - correct answer 1) HCl placed at one end
of the test tube, ammonia solution at the other.
2) Where they meet, a ring of Ammonium Chloride appears.
3) The diagram shows that the ammonia is closer to the ring,
showing that ammonia must have travelled faster, showing it's a
lighter gas.
Experiment for Dilution? - correct answer 1) Put a coloured
substance in a solvent e.g. food colouring in water.
2) Over the time, the colour levels out but is weaker than the
original solution- Dilution
3) More heat = more kinetic energy = happens faster, rate of
dilution quicker.
,EDEXCEL IGCSE CHEMISTRY EXAM
What is filtration? - correct answer Making a barrier which one
component of a mixture can pass through but the other is
caught by.
What is distillation? - correct answer When one substance is
evaporated off while the other remains.
What is fractional distillation? - correct answer A mixture is
evaporated and rises up a tube. Different substances have
different boiling points and so will condense at different
temperatures. As the mixture travels up the tube, the
temperature decreases, substances are collected at different
places. Separates a mixture into its different parts.
What is crystallisation? - correct answer A solution is warmed,
allowing the solvent to evaporate; the solution is now left to
cool and will form crystals.
What is chromatography? - correct answer Chromatography paper
is placed in a substance; the different components of the
substance will travel at different speeds due to the size of the
particles.
,EDEXCEL IGCSE CHEMISTRY EXAM
How can information from chromatograms be used to identify
the composition of a mixture? - correct answer Chromatography
paper is placed in a solvent- the different compounds will travel
at different speeds due to the size of their particles.
What is the atomic number? - correct answer Number of protons
(same as the number of electrons)
What is the atomic mass number? - correct answer Number of
neutrons & protons together
What are isotopes? - correct answer Atoms of an element with the
same number of protons but a different number of neutrons
What is the RAM (relative atomic mass)? - correct answer the mass
of one atom of an element in relation to Carbon
How do you work out the relative formula mass (Mr) from the
relative atomic mass (RAM)? - correct answer (Number of that
element in a molecule x its RAM) + (Number of other elements
in a molecule x its RAM)
, EDEXCEL IGCSE CHEMISTRY EXAM
Triangle for carrying out equations using AR & Mr - correct answer
Moles (mol) = Mass (g) / RFM (Mr)
How do you work out moles for a gas? - correct answer Moles =
Mass (g) / 24,000 cm3 (24dm3)
Difference between a liquid (l) and an aqueous solution? - correct
answer an aqueous solution is a solid dissolved in a liquid.
How can you obtain the formula of a simple compound
experimentally? - correct answer 1) Weigh your compound of two
elements.
2) Remove an element through a reaction. Weigh again. This
gives you the individual mass of both elements in the
compound.
3) Work out the formulae by dividing the weight by its Ar.
egg 22g with an AR of 11 = 22/11 = 2
How to work out the empirical formula? - correct answer 1) Find
the masses of each element in a compound by taking each
element out and weighing.
2) Turn these masses into percentages of the compound.
