AQA GCSE Combined Science Chemistry - Chemical Analysis
Studied by 0 people
Learn
Practice Test
Spaced Repetition
Match
Flashcards1/24
There's no tags or description
Looks like no tags are added yet.
Name | Mastery | Learn | Test | Matching | Spaced |
|---|
No study sessions yet.
25 Terms
What is a pure substance in chemistry?
A single element or compound, not mixed with anything else.
How can you tell if a substance is pure?
It has a fixed melting and boiling point.
What is a formulation?
A mixture designed for a specific purpose, made in definite proportions.
Give examples of formulations.
Medicines, paints, fuels, cleaning agents.
What is chromatography used for?
To separate and identify substances in a mixture (like inks or dyes).
What is the mobile phase in chromatography?
The solvent that moves through the paper.
What is the stationary phase in chromatography?
The paper that stays still
What determines how far a substance travels in chromatography?
Its solubility and how strongly it sticks to the paper.
What is the Rf value?
Rf = distance moved by substance Ă· distance moved by solvent
What is the Rf value always between?
0 and 1
What is a positive test for hydrogen gas?
A lit splint makes a squeaky pop.
What is a positive test for oxygen gas?
A glowing splint relights.
What is a positive test for carbon dioxide gas?
Limewater turns cloudy.
What is a positive test for chlorine gas?
Damp litmus paper turns white (bleached).
What is the flame test for lithium?
Crimson red flame.
What is the flame test for sodium?
Yellow flame.
What is the flame test for potassium?
Lilac flame.
What is the flame test for calcium?
Orange-red flame.
What is the flame test for copper?
Green flame.
What happens when sodium hydroxide is added to aluminium, calcium, or magnesium ions?
White precipitate forms.
How do you distinguish between aluminium and the others with sodium hydroxide?
Aluminium dissolves in excess sodium hydroxide.
What colour precipitate does copper(II) form with sodium hydroxide?
Blue precipitate.
What colour precipitate does iron(II) form?
Green precipitate.
What colour precipitate does iron(III) form?
Brown precipitate.
Which ion causes a white precipitate with silver nitrate?
Chloride ions (in the presence of nitric acid).