- made from a mixture of cement, sand, aggregate (crushed rocks) and water - very strong - easily molded - reinforced with steel rods

- cement is the "glue" for concrete - cement is lime (calcium oxide of CaO)

Chemistry: Final Exam Flashcards by Joana B:B

What are examples of ceramics?

dishes
pots/pottery
plates
china: fancy pots, tea cups
porcelain: toilet, wash basins
brick: houses, pizza ovens
glass: windows, jars, beakers

How well did you know this?

Not at all

Perfectly

What are the properties of ceramics? (hint: 6)

heat resistant
not deform
wear resistant
brittle
insulators
electricity resistant

How well did you know this?

Not at all

Perfectly

How are ceramics made?

kiln 1000ºC

- SiO2 (what we need to make sand)

How well did you know this?

Not at all

Perfectly

What are polymers?

Long chains of repeating molecules

How well did you know this?

Not at all

Perfectly

What is a monomer?

One molecule that can be joined to form a polymer

How well did you know this?

Not at all

Perfectly

What is elastic?

tries to return to original shape

How well did you know this?

Not at all

Perfectly

What is plastic?

can be reshaped and hold new shape

How well did you know this?

Not at all

Perfectly

What are the properties for Natural rubber?

Soft and sticky when hot

- Hard and brittle when cold

How well did you know this?

Not at all

Perfectly

What is Vulcanisation?

heating rubber with sulphur

- vulcanised rubber is elastic but not plastic because of the heavy, strong cross links

How well did you know this?

Not at all

Perfectly

What is Polymerisation?

process by which we make polymer

How well did you know this?

Not at all

Perfectly

What is an Exothermic reaction?

transfers energy to surroundings

- gets hot!

How well did you know this?

Not at all

Perfectly

What is an Endothermic reaction?

energy taken (“consumed”) from surroundings

- gets cold! or requires constant heat

How well did you know this?

Not at all

Perfectly

What are Composite materials?

Combinations of two or more materials, with some of the properties of each
Many are made by fixing fibres into liquid resin which then sets hard

How well did you know this?

Not at all

Perfectly

What is Safety glass?

-shatters and stays together when broken

How well did you know this?

Not at all

Perfectly

What are examples of composite materials?

Concrete
Paper
Plywood

How well did you know this?

Not at all

Perfectly

What is GRP? (hint: 6)

Glass-Reinforced Plastic
Fiberglass
Lightweight
Strong
Semiflexible
Easily molded into shapes

How well did you know this?

Not at all

Perfectly

What is Kevlar and Resin?

“carbon and fibre”

- strong and lightweight

How well did you know this?

Not at all

Perfectly

What is concrete?

made from a mixture of cement, sand, aggregate (crushed rocks) and water
very strong
easily molded
reinforced with steel rods

How well did you know this?

Not at all

Perfectly

What is cement?

cement is the “glue” for concrete

- cement is lime (calcium oxide of CaO)

How well did you know this?

Not at all

Perfectly

What are the problems with materials?

finite (limited)

- creates harmful compounds by products

How well did you know this?

Not at all

Perfectly

What are the harmful compounds?

Carbon monoxide (CO): caused by incomplete combustion (needs more O2)
Sulfur dioxide (SO2): caused by sulfur impurities in fuel, forms acid rain
Nitrogen Oxides (NOx): caused by high temperatures, also forms acid rain
Carbon dioxide (CO2): a green house gas

How well did you know this?

Not at all

Perfectly

What is the word equation for combustion?

C2H6 + O2 -> CO2 + H2O (+CO)-> when insufficient O2

What is Biodegrability?

-ability to break down in nature over time

Why do we need to recycle?

We know there are finite materials on earth
We are consuming!
We will run out

What are landfills?

- ugly; smelly - occupy land - dangerous: leaks toxic substances, release gases (CO2, methane -H4- "Greenhouse") - expensive to run

What are the ways of recycling?

- Composting - Paper (recycling) - Glass (recycling) - Plastic (re-using)

What are the properties of Metals? (hint:5)

- High melting points - Good conductors of electricity - Good conductors of heat - High density - Malleable

Properties of asbestos? (hint:5)

- Excellent electrical insulator - Naturally occurring mineral - Fire-proof - Weavable - Used in construction: roofing, walls, floor tiles

Why are asbestos bad?

- Breathing in fibers through mouth and nose - They stab the lungs and scar lung tissue - Leads to lung cancer and other problems

How can we deal with asbestos?

- Seal or cover - Monitor the air - Take precaution when demolishing - Check for it

What are Chlorofuorocarbons (CFC)?

- Used in aerosol spray and refrigerants | - Create holes in the Ozone layer, which protects us from UVC (ultraviolet) radiation from the sun

What is the Ozone layer?

-Ozone layer is "natural sunscreen" from UVC radiation

What are the CFCs elements?

- O2: diatomic oxygen - O: atomic oxygen - O3: ozone

What is an explosion?

- It is a chemical reaction that causes a destruction - exothermic - releases heat, sound and force-> can destroy or cause mess (shock)

What properties do physical changes have?

- state changes (boiling, melting) - No new substance - Easily reversible!

What properties do chemical changes have?

- new products formed | - not easily reversed

What is pressure?

- force exerted upon object - in gases, causes by collisions - pressure increases: - increase temperature-> energy - increase particles-> increase in collisions! - decrease volume-> increase collisions

How are explosions in a physical change caused?

- caused by phase change - rapid expansion of volume - intermolecular forces are overcome

How are explosions in a chemical change caused?

-Caused by a release of energy in a chemical reaction (breaking and making of bonds)

What is the word equation for Propanes?

C3H8 + O2 -> CO2 + H2O

What does "reactivity" mean?

- "response" to other molecules/elements | - relation between protons and electrons

Memorise:

Metal + Water -> metal hydroxide Metal + acid -> salt + hydrogen

What are examples of exothermic rxns?

- Sodium hydrogen + hydrochloric acid (neutralisation) | - Methane + Oxygen -> Carbon dioxide + water (combustion of hydrocarbon)

Why does Surface Area malter?

-high S.A increases reaction rate

What does an Oxidizer/ Oxidizing Agent do?

-Provide oxygen for combustion reactions

What is the word equation for Electrolysis?

AI2O3 + C -> no rxn

Characteristics of Electrolysis?

anodes are positively charged - they attract anions (negative ion) anthodes are negatively charged -they attract cations (positive ions)

What is Electrostatic attraction?

-attraction between oppositely changed particles

What is Hydrogen Bonding?

-Electrostatic attraction between the proton (+) of a hydrogen and lone electron pairs (-)

What are Pure Substances?

-all particles are the same

What is a Mixture?

-contains different particles

What is an Element?

-substance made from only one type of atom

What is a Compound?

-substance made from different types of atoms joined together

What are examples of separations techniques?

- Filtration - Separating Funnel - Distillation - Fractional Distillation