GCSE CHEMISTRY 9 TO 1 EDEXCEL
PAPER 1 HIGHER TIER MAY 2025
COMPLETE QUESTIONS AND MARK
SCHEME WITH DETAILED
EXPLANATIONS GRADE A+
◉ Recall the names used for the interconversions between the three
states of matter. Answer: (freezing instead of solidification in diagram)
◉ Explain the changes in arrangement, movement, and anergy of
particles during interconversions. Answer: As a substance melts and
boils, they move less and arrangements become more random. And as
they freeze and condense they move less and return to fixed positions
◉ Predict the physical state of a substance under specified conditions,
given suitable data. Answer: Below M.P: Solid
Between M.P and B.P: liquid
above B.P: gas
◉ Explain the difference between chemically pure and its everyday use.
Answer: Chemically pure: the composition cannot be changed and is
same in all parts of the substance
◉ Explain the difference between a pure substance and a mixture.
Answer: 'Pure' substance: made up of several elements
Mixture contains elements or compounds not chemically bonded
, ◉ how can you tell the difference between a pure/impure substance from
a time/temperature graph. Answer: Impure: melts over a range of
temperatures indicating that it contains more than one element
Pure: Sharp melting point because there is only one elements
◉ Risk: Spitting of liquid while boiling. Answer: Precaution: Eye
protection, using steam to heat, removing bunsen burner form solution
before it is dry
◉ Risk: burning of hand by flask/burner. Answer: Precaution:
tongs/gloves
◉ Mixtures separated by simple distillation. Answer: water
◉ Mixtures separated by fractional distillation. Answer: two or more
liquids
◉ Mixtures separated by filtration. Answer: a solution with solvents ad
solutes
◉ Mixtures separated by crystallisation. Answer: a solution with
dissolved solutes
PAPER 1 HIGHER TIER MAY 2025
COMPLETE QUESTIONS AND MARK
SCHEME WITH DETAILED
EXPLANATIONS GRADE A+
◉ Recall the names used for the interconversions between the three
states of matter. Answer: (freezing instead of solidification in diagram)
◉ Explain the changes in arrangement, movement, and anergy of
particles during interconversions. Answer: As a substance melts and
boils, they move less and arrangements become more random. And as
they freeze and condense they move less and return to fixed positions
◉ Predict the physical state of a substance under specified conditions,
given suitable data. Answer: Below M.P: Solid
Between M.P and B.P: liquid
above B.P: gas
◉ Explain the difference between chemically pure and its everyday use.
Answer: Chemically pure: the composition cannot be changed and is
same in all parts of the substance
◉ Explain the difference between a pure substance and a mixture.
Answer: 'Pure' substance: made up of several elements
Mixture contains elements or compounds not chemically bonded
, ◉ how can you tell the difference between a pure/impure substance from
a time/temperature graph. Answer: Impure: melts over a range of
temperatures indicating that it contains more than one element
Pure: Sharp melting point because there is only one elements
◉ Risk: Spitting of liquid while boiling. Answer: Precaution: Eye
protection, using steam to heat, removing bunsen burner form solution
before it is dry
◉ Risk: burning of hand by flask/burner. Answer: Precaution:
tongs/gloves
◉ Mixtures separated by simple distillation. Answer: water
◉ Mixtures separated by fractional distillation. Answer: two or more
liquids
◉ Mixtures separated by filtration. Answer: a solution with solvents ad
solutes
◉ Mixtures separated by crystallisation. Answer: a solution with
dissolved solutes
