1. Calderglen High School
Formulae 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22
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2. What is the CHEMICAL FORMULA of a substance?1
What is the CHEMICAL FORMULA of a substance?
answer
The ratio of atoms of each element in the substance
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3. A group of atoms joined together by covalent bonds
What is a molecule? 2
answer
A group of atoms joined together by covalent bonds
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4. What is the molecular formula for this molecule?3
answer
C2H6O H H H C C O H H H
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5. What is the correct formula for this molecule?4
answer H
CHCl3 C Cl Cl Cl
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6. What is the chemical formula of hydrogen?5
answer H2
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7. How many atoms of each element are present in a molecule of H2O?6
answer
H = 2
O = 1
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8. How many atoms of each element are present in a molecule of C6 H12O6?7
answer
C = 6
H = 12
O = 6
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9. What is meant by the prefix:- Mono?8
answer
Mono = 1
ie carbon monoxide molecules contain one oxygen atom (CO)
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10. What is meant by the prefix:- Di?9
answer
Di = 2
ie carbon dioxide molecules contain two oxygen atoms (CO2)
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11. What is meant by the prefix:- Tri?10
answer
Tri = 3
ie sulphur trioxide molecules contain three oxygen atoms (SO3)
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12. What is meant by the prefix:- Tetra?11
answer
Tetra = 4
ie carbon tetrachloride molecules contain four chlorine atoms (CCl4)
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13. What is the chemical formula of carbon tetrachloride?12
answer
CCl4
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14. Use the prefix method to name the compound with the formula N2O413
answer
Dinitrogen tetroxide
(tetraoxide)
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15. 14 Valency = combining power of an atom Group 1 2 3 4 5 6 7 8
What is VALENCY?
answer
Valency = combining power of an atom
Group
Valency
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16. What is the valency of the Group 7 elements?15
answer 1
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17. What is the valency of the Group 2 elements?16
answer 2
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18. Describe how to work out the chemical formula of a compound?17
Describe how to work out the chemical formula of a compound?
Symbols
Valencies
Swap
Divide
answer
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19. What is the chemical formula of hydrogen sulphide?18
answer
Symbols H S
Valencies
Swap
Divide not needed here
ANSWER:
H2S
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20. What is the chemical formula of calcium oxide?19
Symbols Ca O
Valencies
Swap
Divide
answer
ANSWER:CaO
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21. Write the formula for silver (I) chloride20
Write the formula for silver (I) chloride
Symbols Ag Cl
Valencies
Swap
Divide not needed here
answer
ANSWER: AgCl
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22. What is the valency of iron in iron (III) oxide?21
answer 3
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23. Roman Numerals in brackets eg copper (II) chloride = valency 2
How is the valency of a transition metal shown in the names of its compounds? 22
answer
Roman Numerals in brackets eg copper (II) chloride = valency 2
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