Chemistry 1 - a

Question 1

What does the structure of a nucleus look like?

Answer 1

Nucleus in the middle
Nucleus is made from protons and neutrons
Electrons in outer shell move around nucleus
Shells hold 2,8,8,10 electrons

Question 2

Properties of Protons, Neutrons and Electrons

Answer 2

Protons = positive - 1
Neurons = neutral - 1
Electrons = negative - 1/2000

Question 3

What is an element?

Answer 3

Elements consist of only one type of atom

Question 4

What are the mass and atomic numbers?

Answer 4

Mass number is top = no of protons and neutrons

Atomic number is bottom = no of protons/electrons

Question 5

What is a compound?

Answer 5

Different atoms that have reacted and formed chemical bonds with each other. Made through ionic, covalent or metallic bonding.

Question 6

What is ionic bonding?

Answer 6

When a metal and a non-metal gain/loose electrons to get a full outer shell. Metals loose electrons to form positive ions - non metals gain electrons to form negative ions.

Question 7

What is covalent bonding?

Answer 7

When two non-metals share electrons with each other to get a full our shell.

Question 8

What is limestone?

Answer 8

Calcium Carbonate

CaCO3

Question 9

What does limestone make when it is thermally decomposed?

Answer 9

Calcium oxide and carbon dioxide.

CaO + CO2

Question 10

What is thermal decomposition?

Answer 10

When a substance is chemically changed into at least 2 new substances when heated.

Question 11

What happens to calcium carbonate when it reacts with an acid?

Answer 11

It makes a calcium salt, carbon dioxide and water.

Question 12

What is made when calcium oxide is mixed with water?

Answer 12

Calcium hydroxide

Question 13

What do we use calcium hydroxide for?

Answer 13

In water it is limewater and can be used to test for carbon dioxide. If you bubble gas through it and it turns cloudy theres CO2 in it.

Question 14

How is cement, mortar and concrete made?

Answer 14

Cement - powdered limestone in a kiln with powdered clay
Mortar - Cement + sand and water
Concrete - Cement + sand + aggregate

Question 15

What are the bad things about quarrying limestone?

Answer 15

^ Creates huge, ugly holes that permentantly change the landscape
^ Noise and dust pollution
^ Destroys habitats
^ Extra transports in area means more pollution and traffic
^ Waste materials create ugly tips.
^ People can have breathing problems
^ Fossil fuels are burnt in process

Question 16

What are the good things about quarrying limestone?

Answer 16

^ Provides us with houses and roads, dyes, paints and medicines.
^ Limestone neurtalises acidic soil.
^ Neutralises sulfur dioxide in chimmneys
^ Provides jobs
^ Boosts local economy and businesses.
^ After quarrying they usually restore the landscape as much as possible.

Question 17

Advantages and disadvantages of limestone products?

Answer 17

^ Widely available and cheaper than granite or marble.
^ Hard-wearing but looks attractive
^ Wont rot and can't be eat by animals
^Fire resistant
^ Doesn't corrode

But
Concrete looks very unattractive

Question 18

What is an ore?

Answer 18

A rock which contains enough metal it is economically worthwhile to extract from.

Question 19

Why can the economics (profit) of metal extraction change over time?

Answer 19

^ Market price drops
^Prices increase so its not worthwhile to extract
^ With improved technology you can extract metal that before was not worthwhile

Question 20

How are metals extracted from ores?

Answer 20

Reduction - chemically (with carbon )

Electrolysis - splitting with electricity

Question 21

What happens when an ore is reduced?

Answer 21

Oxygen is removed to leave the element on its own.

Question 22

When will reduction work?

Answer 22

Metals higher than carbon must be extracted with electrolysis
Below carbon then they can be reduced in a blast furnace with carbon. As carbon will only take oxygen from those that are lower in the reactivity series.