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
