CHEM UNIT 4 UGHHHHHHH

Question 1

1. Rock is usually a mixture of ___.
2. Metals have different ____, A few unreactive metals do not react with other
   elements, They are found naturally in their ____ state.

Answer 1

Minerals
reactivities, free

Question 2

1. Most metals are too ___ to exist on their own in the ground. They exist with other
   elements as ___.
2. The compounds are usually ___, ___ and ____. These compounds are called
   minerals.
3. What are ores?

Answer 2

reactive, compounds
oxides, carbonates, sulphides
Rocks containing minerals in concentrations high enough for economical extraction.

Question 3

What are some ways of extracting metals from their ores?

Answer 3

Physical method ( Very unreactive metals )
Heating ore alone ( Unreactive metals )
Carbon reduction / Heating ore with carbon ( Moderately reactive ores )
Electrolysis ( Reactive metals )

Question 4

Reactive metals such as aluminium and magnesium, are extracted by electrolysis
of their _____ ores. This is a very costly process because it uses a lot of ____ energy.

Answer 4

molten, electrical

Question 5

1. What is the word equation extracting mercury from cinnabar (mercury sulphide)?
   And what is extraction process?
2. What is the word equation extracting lead from lead(II)oxide? And what is the
   extraction process?

Answer 5

1. Cinnabar + Oxygen -(heat)-> Mercury sulphide + Sulphur dioxide, Heating ore alone
2. Lead(II) oxide + carbon -(heat)-> Lead + Carbon dioxide, Carbon reduction/Heating ore with carbon

Question 6

What do limestone, chalk and marble are rocks which contain mainly what? And what is its natural form?

Answer 6

The mineral calcite, calcium carbonate

Question 7

Skeletons and shells of sea animals are made up of ______. After dieing, the bodies are covered by mud and sand. After millions of years under high temperature and pressure, calcium carbonate changes to ___, ___ and marble.

Answer 7

calcium carbonate, chalk, limestone

Question 8

When calcium carbonate is strongly heated, it decomposes to form ______ and carbon dioxide
What is the word equation?

Answer 8

Calcium oxide,
Calcium carbonate -(heat)-> Calcium oxide and Carbon dioxide

Question 9

Slaked lime is formed when?
What is the word equation?

Answer 9

A few drops of water are added to calcium oxide,
Calcium oxide + water –> Calcium hydroxide ( slaked lime)