Flashcards in Topic #4: Chemical Changes Deck (18):
What happens when metals react with oxygen?
A metal oxide is produced
This is a oxidation reaction because it gains oxygen
State the series of reactivity.
-------------- react with cold water
------------------ react with steam
--------------reaction boundary for dilute acid
-------------- reaction boundary for oxygen
------------------ No reaction
What will displace a metal from its compound?
A more reactive metal
How are metals found?
Unreactive metals (eg. gold) are found in the earth
Most metals require extraction from ores via chemicla processes
How are metals extracted from ores?
The oxide is reduced (loses oxygen) by bioleaching
ONLY IF IT IS ECONOMICALLY VIABLE
What is phytomining?
Planting a plant over an ore and letting the roots absorb ions, then burn it to get the ions off
What is OIL RIG in terms of electrons?
List the acid reactions
Acid + metal = salt and hydrogen
Acid + metal (hydr)oxide = salt and water
Acid + metal carbonate = salt and water and carbon dioxide
Acid oxide + base = salt and water
What happens in neutralisation?
Acids react with alkalis/bases to form salts and water, or carbonates to add carbon dioxide
How are soluble salts made by acids?
By adding solid insoluble substances
What do all acids have in aqueous solutions?
What do all alkalis have in aqueous solutions?
How ionised are different strength acids?
Strong acids (eg nitric, sulphuric, hydrochloric) are fully ionised
Weak acids (eg citric, ethanoic) are only partially ionised
What factor does the H ion concentration decrease by per pH?
What happens at the electrodes during electrolysis?
Ions are discharged
What are cations, cathodes, anions and anodes?
Anode- positive, attracts cations (negative charge)
Cathode- negative, attracts anions (positive charge)
When are ions replaced and where?
Cathode: If they are less reactive than hydrogen (oxidation)
Anode: If they are less reactive than hydroxide (reduction)