Topic #4: Chemical Changes Flashcards
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.
Potassium Sodium Lithium Calcium -------------- react with cold water Magnesium Aluminium -CARBON- Zinc Iron ------------------ react with steam Tin Lead --------------reaction boundary for dilute acid -HYDROGEN- Copper Silver -------------- reaction boundary for oxygen Gold Platinum ------------------ 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?
Oxidation
Is
Loss
Reduction
Is
Gain
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?
H+ ions
What do all alkalis have in aqueous solutions?
OH- ions
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?
Ten
What happens at the electrodes during electrolysis?
Ions are discharged
