Metals Flashcards
Name the 6 physical properties of metals
- Metals are ductile (able to be stretched into wires without losing toughness)
- Metals are malleable (able to be bent into different shapes without breaking)
- Metals are good conductors of electricity and heat
- Metals have high melting and boiling points and generally are solids at room temperature.
- Metals have high density
- Metals are generally strong and shiny
Metals have high melting points. Name one metal that is an exception to this rule.
Mercury has a low melting point (~39°C) and exists as a liquid at room temperature.
Metals have high density. Which group of metals are an exception to this rule?
Group I metals such as lithium, sodium and potassium have low densities and float on water.
Why are alloys stronger and harder than pure metals?
- Pure metals are soft as the layers of metal atoms are in an orderly arrangement and would slide over one another easily when an external force is applied to them
- In alloys, since the atoms have different sizes, the orderly arrangement of the metal atoms would be disrupted, making it tougher to slide over as easily. Hence, alloys are much stronger and harder.
What are alloys?
An alloy is a mixture of a metal with one or few other metal or non-metal elements.
Name 4 alloys and their respective components.
- Steel (iron, carbon)
- Stainless steel (iron, carbon, nickel)
- Brass (copper, zinc)
- Bronze (copper, tin)
Give the initial of each metal in the reactivity series, from most reactive to least reactive.
PSCMACZITLHCMSG
What is the method of extraction for PSCMA?
Compound broken down through electrolysis
Method of extraction for ZITL?
Compound broken down by reduction with carbon
Method of extraction for CMSG?
Compound broken down by thermal decomposition
Describe the reaction between PSC and water.
Reacts readily with cold water and explosively with steam
Describe the reaction between MACZI and water
Either reacts slowly or doesn’t react at all with cold water. All of them reacts with steam.
Take note that aluminium is covered by a thin layer of aluminium oxide and can only react with steam if the oxide layer is removed.
Describe the reaction between TLCMSG and water
Does not react with cold water or steam
Describe the reaction between PSCMAZITL and acid
All reacts with acid, ranging from vigorously to moderately to slowly
Describe the reaction between CMSG and acid.
Does not react with acid
In the periodic table, reactivity of metals increases going _____ the group and from ________________.
down; right to left
Why does metal reactivity increase going down the group?
Going down the group, the metal has more valence shells, allowing it to lose its valence electrons more readily to form positive ions, hence it is more reactive.
Metal + H2O (l) ——> ?
Metal hydroxide + H2
Metal + H2O (g) ——> ?
Metal oxide + H2
Metal + Acid ——> ?
Salt + H2
What is a displacement reaction and why can it occur?
- A displacement reaction is when a more reactive metal displaces a less reactive metal from its solution or oxide
- It can happen because the more reactive metal is able to lose its electrons more readily to form cations
When a metal carbonate undergoes decomposition upon being heated strongly, what are the products?
Metal oxide and CO2
Describe and account for the trend between reactivity of a metal and ease of decomposition of its carbonate.
The more reactive a metal is, the ease of decomposition of its carbonate decreases as the carbonate has higher thermal stability
CuO + H2 ——> ?
Cu + H2O
Apart from a more reactive metal, oxides of less reactive metals can also be reduced by _______ and ________.
Carbon; hydrogen
Rusting is the corrosion of iron and steel. State the equation of rusting.
Fe (s) + 3O2 (g) + 2xH2O(I) ——> 2Fe2O3.xH2O (s)
Note: x indicates the amount of water in rust varies
What speeds up rusting? What can you conclude?
- Presence of sodium chloride
- Presence of acidic substances
Iron objects near the sea/near industrial areas/in contact with seawater rust more rapidly
Name the 3 ways to prevent rusting
- Using a protective layer like paint, plastic or electroplating
- Using a sacrificial metal (Protect iron or steel with a more reactive metal)
- Using stainless steel (Stainless steel contains chromium so hard layer of chromium(III) oxide will form on surface of the steel)
Name the 5 reactions taking place in blast furnace
- Production of carbon monoxide: CO2 (g) + C (s) —> 2CO (g)
- Production of carbon dioxide: C (s) + O2 (g) —> CO2 (g)
- Reduction of haematite to iron: Fe2O3 (s) + 3CO (g) —> 2Fe (I) + 3CO2 (g)
- Thermal decomposition of limestone: CaCO3 (s) —> CaO (s) + CO2 (g)
- Removal of impurities: CaO (s) + SiO2 (s) —> CaSiO3 (I)
What are the 3 starting ingredients you put at the top of a blast furnace?
Haematite, coke (carbon), limestone (calcium carbonate)
