Year 10 Chemistry Topics 1-3

Front 1

How did the Earth form?

Back 1

- 4.5 billion years ago, huge rocks collided, generating immense amounts of heat.

- Colliding rocks formed Earth.

- Once surface cooled, heat generated at collision was trapped in core.

- The heat escaped through volcanoes, producing gases like carbon dioxide, hydrogen sulphide, methane and sulphur dioxide.

- This created the atmosphere, which is different to the one today.

- No liquid water due to heat - life as we know it couldn't survive.

- Volcanoes created mountainous terrain, shaping Earth.

- As temperatures cooled, water vapour (created by ice comets impacting with Earth) condensed to make oceans.

Front 2

How do we know that the early atmosphere contained no oxygen?

Back 2

Some of the Earth's oldest rocks contain the compounds iron carbonate (FeCO3) and iron sulphide (FeS). These are compounds that form in the absence of oxygen, proving that there was no oxygen in the atmosphere at the time.

Front 3

Why do scientists look at the atmospheres of other planets?

Back 3

It allows us to see what Earth's atmosphere may have been like before organisms lived on it.

Front 4

Which planets are scientists researching the atmospheres of?

Back 4

Titan (Saturn's moon), Venus and Mars.

Front 5

Describe the features of Titan, Venus and Mars and how they compare to Earth.

Back 5

Mars: volcanic, landscape looks like water once flowed, rocky interior, quite similar to Earth

Venus: "twin planet"; similar size and atmosphere as early Earth, rocky interior, very similar to Earth

Titan: Lots of nitrogen, icy interior, not very similar to Earth

Front 6

What gases are assumed to have made up early Earth's atmosphere?

Back 6

Carbon dioxide

Water vapour

Methane

(Though there's a possibility that is was nitrogen based)

Front 7

What is the word and balanced symbol equation for photosynthesis?

Back 7

Carbon dioxide+water --> glucose+oxygen

6CO(2) + 6H(2)O --> C(6)H(12)O(6) + 6O(2)

(n) = lower case number

Front 8

What do plants use photosynthesis for?

Back 8

To produce glucose, which is their source of energy and nutrition.

Glucose is needed for the plant's respiration to give it energy.

Front 9

Describe stromatolites and how they impacted the Earth's atmosphere.

Back 9

- Oldest living organisms we know of

- Coated in cyanobacteria which was used for photosynthesis

-Photosynthesis added oxygen to the atmosphere

- Carbon dioxide levels dropped and oxygen levels rose because of photosynthesis

Front 10

What happened after oxygen levels rose and carbon dioxide levels decreased because of photosynthesis?

Back 10

1) Temperatures cooled down

2) Water vapour condensed to form oceans

3) Carbon dioxide dissolved into oceans

4) Marine organisms used dissolved CO(2) to make shells from calcium carbonate (CaCO(3))

5) The organisms died and sank to the bottom of the sea.

6) Their shells built up to form sedimentary rocks e.g. limestone

Front 11

How can small changes in our atmosphere occur through volcanic activity?

Back 11

Gases (carbon dioxide, methane, water vapour) are emitted by volcanoes to form the early atmosphere.

Front 12

How can small changes in our atmosphere occur through human activity?

Back 12

- Fossil fuels are burnt - CO(2) into atmosphere

- Cars used - CO(2) into atmosphere

- Respiration - inhale oxygen, exhale CO(2)

Front 13

Where did the nitrogen in the atmosphere come from?

Back 13

Assuming there was always ammonia in the atmosphere:

1) Its decomposition due to UV radiation would've created nitrogen

2) Nitrifying bacteria could have reacted with the ammonia, producing nitrates for plant growth

Front 14

What are igneous rocks made of?

Back 14

Crystals.

Front 15

Explain the difference between intrinsic and extrinsic crystals.

Back 15

Intrinsic: Rocks formed by magma under the surface of Earth. Slower cooling time = larger crystals (more time to merge).

Extrinsic: Rocks formed by lava above Earth's surface. Faster cooling time = smaller crystals (less time to merge).

Front 16

Give an example of an intrinsic and extrinsic rock.

Back 16

Intrinsic: Granite

Extrinsic: Rhyolite

Front 17

How are sedimentary rocks formed?

Back 17

1) Erosion via water

2) Transportation of bits of rock e.g. windspeed

3) Deposition to bottom of ocean

4) Compacted and compressed - forms layers

5) Water squeezed out

6) Cementation - dissolved mineral ions act as glue

7) Fossils - layers build on dead marine organisms

Front 18

What can limestone be used for?

Back 18

- Buildings

- Railway tracks foundations

- Roads

- Cement used in production of glass

Front 19

What advantages does the location of limestone have?

Back 19

1) Mostly uninhabited - more space

2) Higher abundance of limestone

Front 20

What advantages does quarrying limestone have?

Back 20

- Economic growth

- Local materials - cheaper

- Employment opportunities

- Can be turned into nature reserve after

Front 21

What disadvantages does quarrying limestone have?

Back 21

- Not sustainable

- Creates large quarries: unsightly, less tourism, less money

- Can destroy habitats and therefore wildlife

- Noise pollution from machines

- Emissions from machines

Front 22

What compound do limestone, chalk and marble all contain?

Back 22

Calcium carbonate.

Front 23

What happens when calcium carbonate is heated strongly?

Back 23

It thermally decomposes (breaks down) into calcium carbonate and carbon dioxide.

Front 24

What is the symbol and word equation for the thermal decomposition of calcium carbonate?

Back 24

CaCO(3) -heat-> CaO + CO(2)

Calcium carbonate -heat-> calcium oxide + carbon dioxide

Front 25

What happens to copper carbonate when heated?

Back 25

- Goes black

- Becomes copper oxide

- Turns cloudy

Front 26

What's an example of a sedimentary rock?

Back 26

Limestone.

Front 27

How do metamorphic rocks form?

Back 27

When heat and pressure acts on other rocks i.e. igneous and sedimentary, they form new crystals and metamorphic rocks.

Front 28

Describe the crystals of a metamorphic rock.

Back 28

They're interlocking and hard.

Front 29

Give an example of a metamorphic rock and the rock it previously was.

Back 29

Marble.

It can be made either out of chalk or limestone.

Front 30

Which rocks exist in the Earth's crust?

Back 30

Limestone, marble and chalk.

Front 31

True or false: limestone, marble and chalk are all natural forms of calcium carbonate.

Back 31

True.

Front 32

What do all word equations look like?

Back 32

Reactants ---> products

Front 33

What is a precipitation reaction?

Back 33

When two soluble substances (generally liquids) react to form an insoluble (generally solid) product.

Front 34

What is a precipitate?

Back 34

The insoluble substance formed from two soluble substances in a precipitation reaction.

Front 35

What happens when there is carbon dioxide present in limewater?

Back 35

The limewater turns cloudy.

Front 36

Explain the steps of making limewater.

Back 36

1) Thermal decomposition of calcium carbonate

CaCO(3) -heat-> CaO + CO(2)

2) Add water to calcium oxide - heat released, water boils

CaO + H(2)O --> Ca(OH)(2)

3) Add more water - turns Ca(OH)(2) from a solid to an aqueous to create calcium hydroxide solution a.k.a. limewater.

Front 37

What is the more common term for calcium hydroxide solution?

Back 37

Limewater.

Front 38

What's one way of reducing acid rain involving chimneys?

Back 38

Calcium carbonate (a base) is put into chimneys so acids aren't released because they're neutralised.

This reduces acid rain created by emissions of acidic gases.

Front 39

What is indigestion?

Back 39

When too much hydrochloric acid is produced to digest food.

Front 40

What is heartburn?

Back 40

When acid escapes the top of the stomach, causing pain the tube leading to the mouth.

Front 41

What are antacids?

Back 41

Substances containing bases that are used to neutralise excess stomach acid.

Front 42

What is the word equation for neutralisation between an acid and a base?

Back 42

acid + base ----> salt + water

Front 43

What is an alkali?

Back 43

A base dissolved in water.

Front 44

What is the word equation for when an antacid contains a carbonate?

Back 44

acid + carbonate -> salt + water + carbon dioxide

Front 45

Name three ways acids can be neutralised.

Back 45

1) Metal oxides

acid + metal oxide ---> salt + water

2) Metal hydroxides

acid + metal hydroxide ---> salt + water

3) Metal carbonates

acid + metal carbonate -> salt + water + carbon dioxide

Front 46

Name the salts that sulphuric, nitric and hydrochloric acids produce.

Back 46

Sulphuric acid : sulphate salts

Nitric acid: nitrate salts

Hydrochloric acid: chloride salts

Front 47

What is electrolysis?

Back 47

Passing a direct electrical current through an electrolyte to decompose it.

Essentially, it's splitting a compound via electricity.

Front 48

Why is a DC used in electrolysis?

Back 48

If AC was used instead, the ions would keep switching places.

Front 49

What is an anode?

Back 49

A positively charged electrode.

Front 50

What is a cathode?

Back 50

A negatively charged electrode.

Front 51

What is an ion?

Back 51

A charged particle.

Front 52

What is a cation?

Back 52

A positively charged ion.

Front 53

What is an anion?

Back 53

A negatively charged ion.

Front 54

How are ions split apart in electrolysis?

Back 54

Any positive cations will be attracted to the negative cathode.

Any negative anions will be attracted to the positive anode.

Front 55

Why are two test tubes used in electrolysis?

Back 55

To trap the gases produced.

Front 56

What is electrolyte solution?

Back 56

The solution being split using electrolysis.

E.g. hydrochloric acid.

Front 57

What would happen if you used hydrochloric acid as an electrolyte after the ions migrate through the solution?

Back 57

Hydrogen

- Positive hydrogen cations go to negative cathodes to produce hydrogen gas

Chlorine

- Negative chlorine anions go to positive anodes to produce chlorine gas

Front 58

How do you test gas for chlorine?

Back 58

Damp Blue Litmus Paper

1) Hold a piece of damp blue litmus paper in the tube mouth

2) If chlorine is present, it will turn red (as all acids do) and then white, as if it were bleached.

Front 59

How do you test gas for hydrogen?

Back 59

Squeaky Pop

1) Light a splint and put it at the end of the test tube

2) If hydrogen is present, it will make a squeaky pop sound

Front 60

How do you test gas for oxygen?

Back 60

Glowing Splint

1) Light a splint and blow it so that it's glowing

2) Put it in the test tube

3) If oxygen is present, it will relight the flame

Front 61

How do you test gas for carbon dioxide?

Back 61

Limewater

1) If there is CO(2) present in any limewater, it will go cloudy

Front 62

Name two ways of obtaining chlorine.

Back 62

1) Electrolysis of hydrochloric acid

2) Electrolysis of brine solution

Front 63

What are the uses of chlorine?

Back 63

- Swimming pools

- Bleach

- PVC (poly vinyl chloride) - used in drip bags

- Chemical weaponary

- Makes things colourless

Front 64

What are the uses of hydrogen?

Back 64

- Rocket fuel

- Fills weather balloons

Front 65

What are the uses of oxygen?

Back 65

- Respiration

- Mixed with fuel to make hot flames for melting metals

- Hospitals - oxygen masks used for people struggling to breathe

Front 66

What are the dangers of chlorine?

Back 66

- Gas can leak from a chemical factory

- A tanker carrying gas can get in an accident

Overall: can kill nearby people