C5.3

Question 1

1. What is the Earth’s lithosphere?

Answer 1

-the rigid outer layer of the Earth made up of the crust and the part of the mantle just below it

Question 2

1. What is the Earth’s lithosphere made up of?

Answer 2

-a mixture of minerals

Question 3

1. What is a mineral?

Answer 3

A mineral is a solid element or compound with a crystalline structure

Question 4

2. What are diamond and graphite examples of?

Answer 4

• minerals

- giant covalent structures

Question 5

2. What are diamonds and graphite mainly composed of?

Answer 5

-carbon atoms

Question 6

3. What are the properties of diamond and why?

Answer 6

1. high melting and boiling point
   - strong covalent bonds
   - need lots of energy to break bonds
2. very hard
   - rigid structure
   - strong covalent bonds
3. Not soluble
   - (strong covalent bonds and are non polar (no positive or negative regions) so cannot be pulled apart by water like ionic compounds can)
4. can’t conduct elecricity
   - particles not charged (no free electrons)
   - not free to move and carry current

Question 7

3. What is a giant covalent structure?

Answer 7

-a giant structure of atoms held together by strong covalent bonding

Question 8

4. How does the giant structure of graphite differ from that of diamond, and how does this affect its properties?

Answer 8

-both made from carbon atoms
-both not soluble
(strong covalent bonds and are non polar (no positive or negative regions) so cannot be pulled apart by water like ionic compounds can)
-3 covalent bonds instead of 4
= layers can slide past each other
1. =softer
2. =lower melting point
=lower boiling point
-free electrons as only 3 used bonds not 4
3. =can conduct electricity

Question 9

5. What are very abundant elements in the Earth’s crust?

Answer 9

• silicon (Si)
• oxygen (O2)
• aluminium (Al)

Question 10

7. What is much of the silicon and oxygen is present in the Earth’s crust as?

Answer 10

• the compound silicon dioxide

- what sand is made of (silica)

Question 11

7. What is silicon dioxide?

Answer 11

-a compound of silicon and oxygen that is present in the earth’s crust

Question 12

8. What is silicon dioxide and what are its properties similar to?

Answer 12

-it is another giant covalent compound
-it has properties similar to diamond
(High melting/boiling point, hard, not soluble, can’t conduct electricity)