Page 136 - Knowledge Organiser Yr9 24-25

Knowledge Base: Science C1: Atomic Structure and the Periodic Table Year 9
1. Atoms, Elements and Compounds 2. Chemical equations
1.1 What is an atom? The smallest part of an element that can exist. 2.1 How are compounds formed? By the reaction of different elements.
1.2 What is an element? A substance made of only one type of atom.
2.2
How are compounds separated back into their elements?
By chemical reactions.
2.3
What is a chemical reaction?
A chemical change in which one or more new substances are formed. It often involved a detectable energy change (e.g. a change in temperature).
2.4
Name two ways of representing chemical reactions.
Word equations and symbol/formula equations.
2.5
Why do equations need to be balanced?
Due to the law of conservation of mass - the total mass of the reactants is equal to the
total mass of the products
2.6
Balance this equation by using blob diagrams
Zn + O2 → ZnO
2.7
Balance this equation by using blob diagrams
Mg + 2HCl → MgCl2 + H2
1.3
How are atoms of each element represented?
Using a chemical symbol e.g. the chemical symbol for oxygen is O and the chemical symbol of sodium is Na.
1.4
What is found in the Periodic Table?
A list of around 100 different elements which have been arranged.
1.5
What is a compound?
A substance made of two or more different elements chemically combined in fixed proportions.
3. Mixtures
3.1
What is a mixture?
A substance consisting of two or more elements or compounds not chemically combined together.
3.2
Name four ways of separating a mixture.
Filtration, crystallisation, distillation and chromatography.
3.3
How does distillation separate mixtures?
This separates substances according to their boiling points.
3.4
How does filtration separate mixtures?
This separates insoluble substances in the mixture.
3.5
How does crystallisation separate mixtures?
This separates soluble substances in the mixture.
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