AQA GCSE Chemistry Paper 1 Already Graded A+
1. What is the smallest unit of an element?
Answer: An atom is the smallest part of an element.
2. What is a substance that consists of only one type of atom?
Answer: An element is a substance that contains only one type of atom.
3. What are th...
AQA GCSE Chemistry Paper 1 Already Graded A+
1. What is the smallest unit of an element?
Answer: An atom is the smallest part of an element.
2. What is a substance that consists of only one type of atom?
Answer: An element is a substance that contains only one type of atom.
3. What are the symbols that represent elements?
Answer: Chemical symbols are the letters or pairs of letters that represent elements, with the first letter
always capitalized.
4. What are substances made up of atoms from two or more elements?
Answer: Compounds are substances in which atoms of two or more elements are chemically combined.
5. What is a combination of symbols that shows the ratio of elements in a compound?
Answer: A chemical formula is a combination of symbols that shows the ratio of elements in a
compound.
6. Why do chemical formulas matter?
Answer: Chemical formulas help to show the different elements in a compound and how many atoms of
each element one molecule of the compound contains.
7. How can compounds be separated from each other?
,Answer: Compounds can be separated through chemical reactions.
8. What are the starting materials in a chemical reaction?
Answer: Reactants are the starting materials in a chemical reaction, listed on the left side of the
equation.
9. What are the ending materials in a chemical reaction?
Answer: Products are the ending materials in a chemical reaction, listed on the right side of the
equation.
10. What is always equal to each other in a chemical reaction?
Answer: Products and reactants are always equal to each other in a chemical reaction, with no atoms
lost or created.
11. What is a mixture made up of?
Answer: A mixture is made up of two or more elements or compounds that are not chemically
combined.
12. What are the properties of mixtures?
Answer: Mixtures retain their own properties from before, such as color.
13. How can mixtures be separated?
Answer: Mixtures can be separated through physical processes, without creating new substances.
,14. What is filtration used for?
Answer: Filtration is used to separate soluble solids from insoluble solids.
15. What is crystallization used for?
Answer: Crystallization is used to obtain a soluble solid from a solution, by gently warming the mixture
and allowing water to evaporate, leaving crystals of pure salt.
16. What is simple distillation used for?
Answer: Simple distillation is used to obtain a solvent from a solution, by heating a set volume to 100°C
and collecting the condensated liquid.
17. How do you analyze and purify water samples from different sources?
Answer: To analyze and purify water samples, use a pH probe or indicator to check pH, set up
equipment, heat a set volume to 100°C, collect condensed liquid, and measure the mass of solid
remaining to find 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
, What model did *Thomson* make ? ✔️plum pudding model
What was the *plum pudding* model made up of? ✔️- atom contained tiny, negative electrons
- surrounded by a positive charge
What did *Geiger and Marsden* do? ✔️measured the deflection of alpha particles bombarding gold
foil
What did *Geiger and Marsden* conclude about their experiment? ✔️- some alpha particles deflected
- some went straight through
What did *Rutherford* conclude about the *alpha and gold foil* experiment? ✔️- there must be a
positive charge in the center of each atom (new model now called 'nuclear')
What did *Bohr* do? ✔️said that electrons were arranged in levels or orbits around the nucleus
What did *James Chadwick* discover? ✔️neutrons in the nucleus
How big are *atoms*? ✔️- very small
- 0.1nm or 1 x 10^-10m
What do all *atoms* contain? ✔️protons, neutrons, electrons
What is the *relative charge* and *mass* of a *proton*? ✔️1
+1
What is the *relative charge* and *mass* of a *nucleus*? ✔️1
0
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