Chemistry - C1

Question 1

How does making things from limestone create pollution?

Answer 1

• cement factories make a lot of dust, this causes breathing problems.
• Energy needed to produce cement, which comes from burning fossil fuels.

Question 2

What are the advantages and disadvantages of limestone products?

Answer 2

advantages:
- used for building material
- widely available and cheap
disadvantage:
- Have to quarry limestone which leaves scars in landscape
- When in contact with rain water corrodes due to acid rain.

Question 3

Identify two methods to extract copper.

Answer 3

• Displacement reaction ( scrap iron)

- Electrolysis

Question 4

Identify two advantages and disadvantages of metal extraction.

Answer 4

Advantage:
- Useful products are made
- Provides people with jobs
Disadvantages:
- Scars the landscape
- Loss of habitats

Question 5

Give two reasons why we need to recycle metals.

Answer 5

• Mining and extracting takes a lot of energy- burning fossil fuels.
• Energy don’t come cheap so recycling saves money too.

Question 6

Most iron is converted into steel, what two elements does iron contain?

Answer 6

• Carbon

- Iron

Question 7

Names 3 properties a alloy could have.

Answer 7

• corrosion resistant
• Less malleable
• stronger

Question 8

Complete the sentence
Hydrocarbons at the top of the column are ___a__ Flammable and __b_ Viscous and ___c__ volatile.. Hydrocarbons at the bottom have of the column have the __d___ properties.

Answer 8

a) More
b) Less
c) Less
d) Opposite

Question 9

Whats the names, in order, of the first 5 hydrocarbons.

Answer 9

Methane
Ethane
Propane 
Butane 
Pentane

Question 10

What are the advantages and disadvantages of crude oil.

Answer 10

Advanatge:
1)Good fuels
2)Makes raw materials e.g: bags
Disadvanatge:
1)Non renewable
2)Burning causes co2

Question 11

Burning fossil fuels releases co2, what else does it release?

Answer 11

• Particulates

- releases sulfur dioxide if sulfur impurities are in the fuel.

Question 12

What do particulates cause?

Answer 12

Global dimming

Question 13

How is fermentation done?

Answer 13

Using sugar and yeast to make:

sugar –> carbon dioxide + ethanol

Question 14

what is cracking?

Answer 14

splitting long chain hydrocarbons into shorter chain ones.

Question 15

What are the conditions for cracking?

Answer 15

A catalyst and 400-700 degrees

Question 16

How can ethene become ethanol?

Answer 16

hydrated with steam

in presence of catalyst

Question 17

When alkenes are used to make polymers, what is it called?

Answer 17

Polymerization

Question 18

What is polymerization?

Answer 18

Joining lots of monomers to form polymers.

Question 19

Polymers made 200 degrees and 2000 atmospheric pressure is….
Polymers made at 60 degrees and low atmospheric pressure is ….

Answer 19

Flexible and has low density

Rigid and dense

Question 20

what are the Advantages and Disadvantages of polymers

Answer 20

advantages:
- smart polymers used in dental practices.
- light stretchable polymers used to make plastic bags
- memory foam is a smart polymer gets softer as it gets warmer.
disadvantages:
- Most polymers are not biodegradable
- crude oil gets used up so , crude oil prices go up

Question 21

How do we extract oils?

Answer 21

Plant material is crushed.
The press the crushed plant material between metal plates.
Then squash the oil out.

Question 22

Unsaturated oils can be saturated, how?

Answer 22

Adding hydrogen in the presence of nickel catalyst at 60 degrees.

Question 23

What are the properties of hydrogenated oils.

Answer 23

Higher melting point and more solid at room temperature.

Question 24

What do emulsifiers do?

Answer 24

Stop emulsions from separating out and gives them a longer shelf life.

Question 25

What are the advantages and disadvantages to emulsifiers?

Answer 25

Advantage:
Allow food companies to produce food lower in fat with good texture. 
Give food a longer shelf life.
Disadvantage:
Some people are allergic to emulsifiers.

Question 26

What do the hydrophobic and hydrophilic parts of the emulsifier molecule do?

Answer 26

Hydrophilic- Likes water and hates oil ( attracted to water )
Hydrophobic - Likes oil and hates water ( repel water)

Question 27

What does wegener’s theory suggest and why did he suggest this?

Answer 27

He brought forward the ideas that continents fit together like a jigsaw.
He concluded that this was because of continental drift.
He suggested this because he realized there were matching layers of rock and fossils in different continents .

Question 28

Why was wegners theory not accepted?

Answer 28

Scientist believed that Continents were in fixed positions

and that they were formed once connected by land bridges.

other scientist did not respect wegner.

Question 29

How did the earth evolve? (6 marker)

Answer 29

Phase 1 - volcanoes gave out gases (They gave out steam and gases such as nitrogen and carbon dioxide)
Phases 2 - Green plants evolved and produced oxygen (plants photosynthesized and took the co2 in… When these plants died they were buried under layers of sediment along with skeletons and shells of marine organisms and carbon became locked up inside of these sedimentary rocks as insoluble carbonates and fossil fuels.)
phase 3 - Ozone layer allowed evolution of complex animals. (The build up of o2 in atmosphere killed off some early organisms that couldn’t tolerate it but allowed other organisms to evolve. Oxygen created a ozone layer of O3 which blocked the harmful rays of sun. Now there is virtually no co2 left.

Question 30

Explain how life may have formed on earth millions of years ago using the primordial soup theory .

Answer 30

Billions of years ago the earth contained hydrocarbons, ammonia and other gases.
Lightning struck causing chemical reactions between these gases and formed amino acids.
The amino acids collected in a primordial soup - a body of water which life crawled out of.
These amino acids were then combined together to produce organic matter which evolved into simple living organisms.

Question 31

Explain how the primordial soup theory worked.

Answer 31

Nh3, ch4, h2,h20 added together with sparks of electricity. (resembled lightning). These then created amino acids and condensed when made. These collected up together and were called the primordial soup - these chemicals were analysed and were found to produce organic chemicals.

Question 32

How do we distill air and why?

Answer 32

We distill air by:
- Filtering to remove dust.
- Cooling to -200 degrees
- carbon dioxide freezes and is removed ( in case it blocks pipes)
- Liquefied air enters and heated slowly
- remaining gases are separated by fractional distillation. Oxygen and argon come out together so another column is used to separate them .
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Why?
- We distill air to use in the industry.
- Argon in filament lamps and fluorescent tubes.
- Oxygen fuels for rockets.
- Nitrogen fertilizer for soils and plants.