Studied by 0 people
Looks like no one added any tags here yet for you.
What are general physical properties of metals ?
High m.p and b.p
Good conductors of heat and electricity
Malleable and ductile
Why do metals have relatively high melting and boiling points ?
Metals are giant structures with strong metallic bonding.there is strong electrostatic attraction between the positive ions and the negative electrons so lots of energy is required to break these bonds to change the state
In terms of structures why are metals good electrical conductors ?
Metals contain delocalized electrons which are free to move throughout the structure and carry the charge
In terms of their structure why are metals Good thermal conductors?
Metals contain delocalized electrons which are free to move throughout the structure and transfer thermal energy from one place to another
Why are metals Malleable?
The positive ions are arranged in uniform rows which are able to slide over eachother
What is produced when a metal reacts with acid
Salt and hydrogen
What type of reaction occurs when a metal reacts with a acid? Why does this reaction occur
Displacement reaction:
The metal is more reactive than hydrogen so it will displace hydrogen and combine with the ion from the acid
How could you compare how different metals react with an acid ?
-pour the chosen acid into an clinical flask
-add the metal to the flask
-record any observations (including the rate at which bubbles are produced)
-repeat with different metals and compare
What is produced when a metal reacts with cold water ?
Metal hydroxide and hydrogen
What is produced when a metal reacts with steam
Metal oxide and hydrogen
Why is aluminum used for manufacture of aircraft?
-aluminium is used for manufacture of aircraft because it’s strong and have low density
-low density= light weight and easy to move around
Why is aluminum used for the manufacture of overhead electrical cables ?
-good electrical conductivity =delocalized electrons in the structure are free to move and carry the charge
-low density= light weight and easy to move around
Why is aluminium used for food containers?
Aluminum is used for food containers as it is resistant to corrosion
Why is copper used in electrical wiring ?
Copper is used in electrical wiring because it is a good conductor and ductile
Ductile= the metal is able to stretched and pulled through a wire without breaking
What is an alloy?
Alloys are a mixture of metals designed to have properties useful for a particular purpose
Why is gold jewelry often an alloy
Because gold is very soft so it must be alloyed with another metal to make it harder and more suitable for jewelry
How and why is zinc used to make brass ?
Zinc is alloyed with copper to increase the strength and hardness of the metal
Mild steel has 0.25 percent carbon and high carbon steel has 2.5 percent carbon which steel is harder ?
High carbon steel is harder because there are more carbon atoms distorting the uniform layers of iron atoms
Why is stainless steel used to make cutlery
Because it is harder and resistant to corrosion
Whereas pure iron is soft and rust easily
Why are alloys harder than pure metals,using explanations of their structure
Atoms in pure metals are arranged in uniform rows which can slide over eachother easily making them very Malleable
The atoms in alloys are different sizes which distorts the layers meaning they are unable to slide over one another, increasing hardness
