Chemistry 1

Question 1

What are ceramics?

Answer 1

Ceramics are a range of hard, durable non-metallic materials, which are generally unaffected by heat.

Question 2

What are the physical properties of ceramics?

Answer 2

Hard, stiff, strong when compressed, and brittle
high melting points and heat resistant
good insulators of heat and electricity
very unreactive

Question 3

What happens when clay is heated?

Answer 3

When clay is heatd, chemical reactions occur and new compounds, such as china and porcelain, are formed.

Question 4

What happens during the cooling of clay after it had been heated?

Answer 4

During cooling, crystals form and bind together in the ceramic.

Question 5

What determines the size of the crystal? Explain why slow cooling generates bigger crystals

Answer 5

The size of the crystals depends on the speed of cooling. Slow cooling produces larger crystals because the atoms have more time to from a grid-like lattice structure.

Question 6

What is in a lattice structure?

Answer 6

In a lattice structure there are a large number of atoms, in a fixed regular pattern, all joined to each other by strong bonds.

Question 7

What is one reason why ceramics are so stiff?

Answer 7

One reason why ceramics are stiff is because there are so many atoms bonded to each other, with strong bonds, in a rigid structure.

Question 8

Why do ceramics have a high melting point?

Answer 8

They have a high melting point because the high strength of the bonds is the reason why ceramics have such high melting points.

Question 9

What are polymers?

Answer 9

A polymer has molecules made of long chains, which contain repeated groups of atoms.

Question 10

What is rubber and its propeties?

Answer 10

Rubber is a polymer obtained from certain trees. It is soft and sticky when hot but it is hard and brittle when cold.

Question 11

What can we use rubber from trees for?

Answer 11

We use this rubber to make some glues

Question 12

How can the properties of rubber be changed?

Answer 12

The properties of rubber can be changed by vulcanisation

Question 13

What is vulcanisation? What do the sulphur cross links do?

Answer 13

The rubber is heated with sulfur and a reaction occurs that forms cross-links between the long molecules. These cross-links make the rubber much harder and tougher, and stop its properties changing with temperature.

Question 14

What are examples of a natural polymer?

Answer 14

Rubber is a natural polymer. Other examples include DNA, proteins, starch and cellulose.

Question 15

What are synethic polymers?

Answer 15

Synthetic polymers are polymers manufactures using raw materials obtained from crude oil.

Question 16

What is a polymerization reaction?

Answer 16

Polymerisation reactions in which lots of small molecules called monomers join together in chains.

Question 17

What do polymerization reactions like to do (energy expulsion wise)

Answer 17

Polymerisation reactions like this transfer energy to the surroundings, making them warmer.

Question 18

What are exothermic reactions?

Answer 18

Reactions that transfer energy to the surroundings are exothermic

Question 19

What are endothermic reactions?

Answer 19

Reactions that absorb energy from the surroundings, making them cooler, are endothermic.

Question 20

Tell me the monomer, properties and uses of poly(vinyl acetate) PVA

Answer 20

Vintl acetate
unreactive, flexible, plastic
sealents and adhesives

Question 21

Tell me the monomer, properties and uses of polypropene

Answer 21

Propene
Strong, waterproof, flexible, hardwearing
textiles, ropes

Question 22

Tell me the monomer, properties and uses of polytetrafluoroethylene

Answer 22

Tetrafluoroethene
Hard, heat-resistant, low friction surface
Non-stick surfaces for saucepans and baking trays.

Question 23

Composite material examples

Answer 23

Concrete paper plywood

Question 24

What are composite materials

Answer 24

Composite materials are combinations of two or more materials, with some of the properties of each.

Question 25

How are composite materials made?

Answer 25

Many composite materials are made by mixing fibres into a liquid resin which then sets hard.

Question 26

What is concrete

Answer 26

Concrete is a composite material that has been used for thousands of years.

Question 27

How do you make concrete

Answer 27

It is made from a mixture of cement, sand, aggregate (crushed rocks) and water.

Question 28

What is the main material of cement?

Answer 28

Calcium Oxide (lime)

Question 29

How is calcium oxide made

Answer 29

Calcium oxide (lime) is made by roasting calcium carbonate (limestone). The calcium carbonate breaks down in a thermal decomposition reaction: CACO3 (Calcium carbonate) -> CaO (Calcium oxide) + CO2 (Carbon dioxide)

Question 30

What type of reaction is calcium carbonate being roasted?

Answer 30

Very high temperatures are needed because this is an endothermic reaction.

Question 31

What happens when you add water to the concrete mixture

Answer 31

When water is added to the concrete mixture it reacts with the calcium oxide in an exothermic reaction. During exothermic changes energy is transferred to the surroundings, so their temperature rises.

Question 32

Describe the layers of Earth

Answer 32

Crust, Mantle, Inner core, Outer core

Question 33

Mantle

Answer 33

Widest section of the Earth. Made up of semi-molten rock called Magma.

Question 34

Crust

Answer 34

Outer layer of the Earth. The thinnest layer of the four. Solid rock layer that we live upon.

Question 35

Inner core

Answer 35

Hottest part of the Erath. It is solid and made up of iron and nickel.

Question 36

Outer core?

Answer 36

Liquid layer of the core. Extremely hot. Made up of iron and nickel.

Question 37

Sedimentary rock

Answer 37

Example: Limestone, sandstone and chalk Layers: Yes Soft or hard: Soft Grains: small grains weakly held together Porous or non-porous: Porous Formation: Erosion breaks up the rocks and weathering moves the bits away. These grains are fixed together by compaction and cementation. Fossil containing: Yes

Question 38

Metamorphic rock

Answer 38

Example: Marble slate Layers: Thin layers Soft or hard: Harder than sedimentary Grains: Small crystals Porous or non-porous: Non-porous Formation: Extreme pressures and temperatures on sedimentary rock make metamorphic rocks Fossil containing: Twisted fossils

Question 39

Igneous

Answer 39

Example: Granite and Basalt Layers: No Soft or hard: Hardest Grains: Randomly arranged in interlocking big crystals Porous or non-porous: Non-porous Formation: The inside of the earth is very hot – hot enough to melt rocks. The molten rock is called magma. When the magma cools and solidifies igneous rock forms. Fossil containing: No

Question 40

Porous meaning

Answer 40

(of a rock or other material) having minute spaces or holes through which liquid or air may pass.

Question 41

Rock cycle explained?

Answer 41

When molten magma solidifies on or close to the surface of the Earth, igneous rocks are formed. Rocks on the Earth’s surface are broken down by weathering which involves physical, chemical and biological processes. Small particles are transported in rivers and deposited in the sea. Here they are compressed into sedimentary rocks. If these are exposed to heat and pressure they can be converted into metamorphic rocks. If metamorphic rocks are buried even deeper, they can melt due to extreme heat, turning back into magma, restarting the cycle.

Question 42

3 types of recycling

Answer 42

Primary recycling - recyclable material/product is recovered and reused without being changed in any way and usually for the very same purpose Secondary recycling - material/product is reused in some other way Tertiary recycling - involves chemical altering of the material/product in order to make it reusable

Question 43

Why is recycling important?

Answer 43

Preserves wildlife, keeps habitats safe, saves money