Metals | 10 Flashcards
(18 cards)
State the properties of Metals
Metals have giant structures of atoms with strong metallic bonding.
Therefore, most metals have high melting and boiling points.
They can conduct heat and electricity because of the delocalized electrons in their structures.
The layers of atoms in metals are able to slide over each other, so metals
can be bent and shaped , making them malleable
Metal reaction with acid
Salt + Hydrogen
Effervescence is produced due to the bubbles of hydrogen gas being formed
Metal reaction with air / oxygen
Forms metal oxide
Metal reaction with cold water / steam
Reactive metals react with cold water to produce : Metal hydroxide and hydrogen gas
Moderately reactive metals : react slowly in water but react rapidly in steam to form metal oxide and hydrogen
Name uses for metals
Copper for electrical wiring ( ductile and conductive)
Aluminum is used
in aircrafts (low density)
food containers (non - corrosive)
Aluminum forms a oxide layer over it which prevents it from reacting
What is a alloy
Alloys are mixtures of metals / metal and a non-metal , where the metals are mixed together physically but are not chemically combined.
Properties of alloys
Alloys often have properties that can be very different to the metals they contain, for example they can have greater strength, hardness or resistance to corrosion or extreme temperatures
Alloys contain atoms of different sizes, which distorts the regular arrangements of atoms
This makes it more difficult for the layers to slide over each other, so they are usually much harder than the pure metal
State the reactivity series
potassium, sodium, lithium, calcium, magnesium, aluminum, zinc, iron, copper, silver, and gold
Explain how you use the reactivity series to predict the chemical reactions of the metal
The more reactive a metal , the more is its tendency to lose its outer electrons to form its positive metal ion
how do unreactive metals occur
uncombined (not compounds)
Describe how reactive metals are extracted from their ores depending on their position in the reactivity series
Metals which are less reactive are easier to extract and in the case of gold and silver , exists as a free metal , having have not combined with anything as it is not reactive
Metals are extracted by electrolysis
Describe displacement which could be carried out to find the order of reactivity of metals
In a displacement reaction , a more reactive metal displaces a less reactive metal from its salt. Using the reactivity series we can find out which metal will ‘win’ the salt
You can confirm the reactivity series by using “competition reactions”
why is aluminum so unreactive
There is a thick oxide layer in-between aluminum and other elements that prevent it from reacting
How is iron extracted from its ore and what is its ore name
Hematite
Iron ore, coke and limestone are added into a blast furnace
Hot air enters from bottom and goes to top of furnace
Oxygen reacts with coke to form CO2
, which reacts again with coke to form CO
CO is a reducing agent, turning iron oxide into iron
Some carbon will also reduce the iron oxide to iron
Molten iron runs to the bottom of the furnace and then runs off
Describe how to prevent the corrosion of metals
Rusting needs oxygen and water , if one of these is not present , rusting will not take place
- Painting
This separates air and metal , but if the paint is scratched , rusting will start
-Oiling
Prevents from coming in contact with air/moisture
- Coating with plastic
Used in fridges / freezers
-Galvanizing
Dipping object into molten zinc , the more reactive zinc coating slowly corrodes , protecting the metal and losing electrons to it
-Sacrificial protection
Bars of zinc is on top of the metal and because it is more reactive , it forms positive ions better and corrodes before the metal , protecting it , as long as zinc bars are connected to the metal , metal is safe. When zinc runs out , it must be renewed.
Sometimes magnesium is used instead of zinc.
(metal refers to iron or steel)
What metal are stored under oil
Potassium and sodium
How are alloys often harder and stronger than the metals they are composed of
Alloys contain atoms of different sizes, which distorts the regular arrangements of atoms
This makes it more difficult for the layers to slide over each other, so they are usually much harder than the pure metal
What Metals corrodes fastest
Very reactive metals react fast , seen as cooper changes from pink to teal because of reacting and forming verdegris
