Chemistry term 2

Question 1

Describe the structure of silicon (IV) oxide.

Answer 1

Silicon(IV) oxide (SiO₂) has a macromolecular structure similar to that of diamond.

Question 2

State 3 properties which silicon (IV) oxide and diamond have in common.

Answer 2

1. High melting and boiling points
2. Hardness
3. Neither conducts electricity

Question 3

How would you show that silicon (IV) oxide is acidic and not basic or amphoteric?

Answer 3

No Reaction with Acids: SiO₂ does not react with acids like hydrochloric acid (HCl), showing it is not basic or amphoteric.

pH Test: When SiO₂ is added to water, it does not dissolve or change. Its reactivity with bases confirms its acidic character.

Question 4

When ________ ions __________ electrons, reduction occurs.

Answer 4

When positive ions gain electrons, reduction occurs.

Question 5

When ……………. ions …………….. electrons, oxidation occurs.

Answer 5

When negative ions lose electrons, oxidation occurs.

Question 6

Where does reduction take place and where does oxidation take place?

Answer 6

Reduction takes place at the cathode and oxidation at the anode.

Question 7

Calculate the mass of Cu and O₂ required to produce 286 grams of Cu₂O.

Answer 7

Cu= 190 grams are required
O₂= 256 grams are required

Question 8

When 72g of aluminum (Al) reacts completely with oxygen, 102g of aluminum oxide (Al₂O₃) is formed. How much aluminum oxide will be formed when 18g of aluminum reacts?

Answer 8

25.5g

Question 9

How much aluminum is needed to form 51g of aluminum oxide?

Answer 9

36g

Question 10

How much aluminum oxide will be formed when 216g of aluminum reacts?

Answer 10

306g

Question 11

Calculate the mass of 0.5 moles of FeSO₄ · 7H₂O (Iron(II) sulfate heptahydrate).

Answer 11

139g