Topic 5 Seperate Chemistry 1 (Complete) Flashcards
What are 4 properties of transition metals
High melting point
High density
Form coloured compounds
The metals and their compounds used as catalysts
How do metals corrode
When they come in contact with air and water
Rusting is for which metal
When iron corrodes it is called rusting
What are some ways of preventing corrosion
Prevent rusting by coating iron with barrier
Painting
Oiling or greasing
Sacrificial protection
What is sacrificial protection
Placing more reactive metal with the metal so the water and air react with the sacrificial metal instead of the metal your protecting
What is electroplating
When you coat the surface of one metal with another metal using electrolysis
How does electroplating work
Cathode is object your going to electroplate
Anode is the bar of another metal your going to use to electroplate the other
Electrolyte is solution containing metal ions of metal your using for the plating
Explain what happens in terms of electrons during electroplating
Cathode is brass cup(what your electroplating)
Anode is bar of silver(what your using to electroplate)
Electrolyte solution of silver nitrate
Silver ions from electrolyte move to cathode and metal deposited on brass cup
Anode keeps the silver ions in the solution topped up
Cathode Ag+ + e- —> Ag
Anode Ag —> Ag+ + e-
What is an alloy
A combination of a different element added to a metal
Why are alloys usually harder than pure metals
Pure metals all the ions can slide over each other because they are the same size
Alloys have different size atoms so the layers can’t slide over each other easily
Why is iron not used on its own and alloyed with other metals to make alloyed steel
Iron on its own can rust but as steel is less likely to rust
What is aluminium used for and how does its properties help
Aluminium used for aircraft as it has low density and is very strong
What is copper used in and how does its properties help
Copper is used in wiring as it is a good conductor of electricity and is an unreactive metal
Why is gold used in jewellery
Because it is unreactive and doesn’t conduct electricity
What metals alloy to make magnalium and what is it used for
Magnesium and aluminium stronger than aluminium alone and has low density ,used in aircraft
What metals is the alloy brass made of and what is it used for
Copper and zinc,used in musical instruments,door knobs,locks and taps
What is the calculation for percentage yield
Actual yield/theoretical yield*100=percentage yield
What 3 ways is the actual yield usually less then the theoretical yield
Practical losses
Incomplete reactions
Unwanted reactions/side reactions