1. Signs of Chemical Reactions
N3/4 Basics
Signs of Chemical Reactions 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25
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2. 1. What always happens in a chemical reaction?
answer
A new substance is always formed
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3. 2. Give examples of signs that a chemical reaction has occured?
answer
Energy change
Permanent colour change
Gas produced (effervescence)
Solid formed in a liquid
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4. 3. An element is ……… An element is the simplest type of substance.
answer
An element is the simplest type of substance.
It is made up of only 1 type of atom.
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5. 4. What is a GROUP in the Periodic Table?
answer
A column
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6. 5. What are the Group 1 elements called?
answer
Alkali metals
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7. 6. What are the Group 7 elements called?
answer
Halogens
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8. 7. What are the Group 0 elements called?
answer
Noble gases
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8. What are compounds?
answer
Substances made of two or more different types of atom joined together.
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10. 9. What is the difference between a compound and a mixture?
answer
The atoms of a compound are joined together. The substances in a mixture are NOT joined and can be easily separated.
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What element is present in compounds that have names ending in –ate and –ite?
answer
oxygen
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12. 11. What does -ide at the end of the name of a compound indicate?
answer
IDE means that the compound is made up of the TWO elements
e.g. Sodium chloride has SODIUM and CHORINE
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13. (a thing that get dissolved)
12. A solute is ……….
answer
(a thing that get dissolved)
A solute is a substance (usually a solid) which dissolves in a solvent to form a solution.
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14. 13. A solvent is ………… A liquid in which a solute dissolves. answer
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14. What is a SOLUTION?
answer
A solution is formed by dissolving a solute (usually a solid) in a solvent (usually a liquid)
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16. 15. What is an AQUEOUS SOLUTION?
answer
When a substance has been dissolved in WATER
(think of AQUA = water)
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17. 16. What is meant by a property of a chemical?
answer
A property of a chemical is what it is like or what it can do chemically
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18. 17. What is the meaning of the words CONCENTRATED and DILUTE?
answer
Concentrated means a large amount of solute in a small volume of solvent.
Dilute means a small amount of solute in a large amount of solvent
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19. 18. What is a SATURATED solution?
answer
A saturated solution is a solution which cannot dissolve any more solute.
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19. Where in the Periodic Table would you find the METALS and the NON-METALS?
answer
Metals are found to the Left Hand Side of the zigzag line; Non-metals to the Right Hand Side of the zig-zag line
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20. What are ATOMS?
answer
Atoms are very small, particles which make up every element. They are too small to see.
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21. What is a PRECIPITATE?
answer
A precipitate is a solid which is formed when two solutions react together
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23. 22. What is EFFERVESCENCE?
answer
Effervescence is bubbling and fizzing when a gas is given off .
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23. Give the SYMBOLS for the elements - lead, gold, sodium, potassium and iron?
answer
Lead – Pb
Gold – Au
Sodium – Na
Potassium – K
Iron - Fe
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25. 24. What is the difference between COLOURLESS and CLEAR?
answer
Colourless means having no colour. Clear means you can see through something.
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26. 25. SOLUBLE means …….. the substance dissolves in the solvent answer
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