OXFORD AQA GCSE CHEMISTRY PAPER 1
EXAM 2025 VERIFIED QUESTIONS AND
ANSWERS GRADED A+ NEWEST
What is an atom?
smallest part of an element
What is an element?
a substance that contains only one type of atom
What are chemical symbols?
- the letter or pair of letters that represents an element.
- first letter is always capitalized
What are compounds?
substances in which atoms of two or more elements, which are chemically combined
What is a chemical formula?
a combination of symbols that shows the ratio of elements in a compound
,OXFORD AQA GCSE CHEMISTRY PAPER 1
Why are chemical formula used?
- the different elements in a compound
- how many atoms of each element one molecule of the compound contain
How can compounds be separated?
Through chemical reactions
What are reactants?
the starting materials in a chemical reaction (on the left)
What are products?
the ending materials in a chemical reaction (on the right)
What is always equal to each other in a chemical reaction?
products to reactants
- no atoms are lost or made
What is a mixture?
,OXFORD AQA GCSE CHEMISTRY PAPER 1
consist of two or more elements or compounds which are not chemically combined
What are the properties of mixtures?
they retain their own properties from before
e.g. colour
How can mixtures be separated?
by physical processes - no new substances are made
What is filtration?
- used to separate soluble solids from insoluble solids
What is crystallisation?
- used to obtain a soluble solid from a solution
1. Mixture is gently warmed
2. Water evaporates leaving crystals of pure salt
What is simple distillation?
used to obtain a solvent from a solution
, OXFORD AQA GCSE CHEMISTRY PAPER 1
RP Analysis and purification of water samples from different sources
1. Use a pH probe or indicator to analyse the pH of the sample
2. Set up the equipment
3. Heat a set volume to 100oC so that the water changes from liquid to gas
4. Water collects in the condenser and changes state from gas to liquid
5. measure the mass of solid that remains to find the amount of dissolved solids present in the
sample
What is fractional distillation?
- used to separate mixtures in which the components have different boiling points
What is chromatography?
used to separate the different soluble, coloured components of a mixture
What were atoms thought to be in early models?
Tiny spheres that could not be divided into simpler particles
What did Thomson discover in 1898?
electrons - causing the representative of atoms to be changed