Unit 3 Chemistry in Society Flashcards
What are the properties of metals?
What is meant by an alloy?
A mixture of 2 or more elements, one of which has to be a metal
What is a shape memory alloy?
What are the 3 reactions of metals?
With acid
With water
With oxygen
What are the products of reacting metals with water?
A metal hydroxide plus hydrogen
What are the products of reacting metals with acids?
A salt plus hydrogen
What do we call naturally occurring metal compounds?
Ores
What are the 3 methods of extracting metals from ores?
- Heating
- Heating with carbon or carbon monoxide
- Electrolysis
What is meant by “corrosion”
The changing of the surface of a metal from an element to a compound.
What specific name do we give to the corrosion of iron?
Rusting
What is the chemical name for rust?
Iron oxide
What is the chemical test for rusting
What 2 substances are needed for iron to rust?
Water & Oxygen
What 2 categories of rust prevention are there?
Physical
Chemical
What is physical protection from rusting?
Preventing O2 and/or H2O reaching surface of iron
What is meant by “galvanising”?
Coating iron with a layer of zinc
What is chemical protection of iron?
Finding a more reactive metal to “donate” electrons to the iron
What is meant by a monomer?
A small unsaturated molecule
What is a polymer?
A very large molecule consisting of monomers joined together
What is a “thermoplastic” polymer?
Can be reshaped upon heating
What is a “thermosetting polymer”?
Degraded when heated
Which toxic gases can be given off when plastics catch fire?
CO (always possible)
HCl (if Cl atoms are part of chain)
HCN ( if CN group is part of chain)
What does “biodegradable” mean?
Can be broken down by the action of bacteria
How are polymers named?
The prefix “poly” is put in front of monomer name
e.g but-1-ene becomes polybut-1-ene
pent-2-ene becomes polypent-2-ene
What are some advantages of using plastics ?
long lasting
easily moulded
cheap
strong
What are some disadvantages of using plastics (addition polymers)?
non-biodegradable
come from crude oil which is finite
difficult to recycle
limited heat range and can give off toxic fumes
What 3 elements are needed for plant growth?
What is a fertiliser?
A substance that contains the natural elements needed for healthy plant growth
What is eutrophication?
The introduction of excess nutrients to a water system
What are the 3 ways of extracting metals from ores?
Electrolysis ( Al and above)
Heating with carbon ( Cu to Mg)
Heating ( Below Cu)
How does the reactivity of metals affect their reactions with water, acids, and oxygen?
What is an electrochemical cell?
An arrangement that produces electricity through a chemical reaction
What is the set up for a simple electrochemical cell?
What is an electrolyte?
What is the purpose of the electrolyte?
To complete the circuit
Where does the reaction(s) take place in an electrochemical cell?
On the surfaces of the electrodes (metal strips)
In which direction do the electrons flow in an electrochemical cell?
From the metal higher in the electrochemcial series to the metal lower
Why do cells “run out” and stop working?
The chemical run out
What are the 2 types of fertiliser?
Natural ( organic)
Synthetic ( artificial)
Name 2 examples of natural fertilisers
Give an advantage and disadvantage of natural fertilisers?
Adv: Environmentally friendly
Disadv: Lower concentration of nutrients
What is the impact of NPK fertilisers on the environment?
What is meant by “nuclear fusion”
2 light nuclei joining together to produce a heavier nucleus
Whys might nuclear fusion be important?
It releases a massive amount of energy which could be used if harnessed safely
Where were all the natural chemical elements formed?
In the stars by nuclear fusion
State how heavier elements (>Fe) are made.
During supernova explosions
What causes radioactivity?
Unstable nuclei emits waves or particles to obtain stability
Give some natural sources of background radiation
Give some artificial sources of background radiation
How can we test for the presence of some metal ions?
By the colours they produce in a flame
