Chemical Changes Flashcards
(29 cards)
What is a metal ore
A metal which is economical to extract
What is oxidation ( in metal oxides)
When A metal reacts with oxygen in air
Oxygen + iron= iron oxide
Reactivity series order
Please potassium
Stop sodium
Calling calcium
Me magnesium
A aluminium
Careless (carbon)
Zebra zinc
Instead iron
Try tin
Learning lead
How (hydrogen)
Copper
Saves silver
Golden
What is reduction ( in terms of reactivity scale )
If a metal is lower in reactivity scale than carbon it can be extracted using carbon this is called reduction because oxygen will be lost eg
Iron oxide + carbon = iron + carbon dioxide
What is REDOX reaction
When oxidation and reduction occurs in the same reaction.
For reduction reaction you just have to identify what has been oxidised and what has been reduced
Eg
Lead oxide + carbon -> lead +carbon dioxide
Lead has been reduction
Carbon has been oxidised
Acids reacting with metals
Acid+metal = salt + hydrogen
Eg hydrochloric acid + copper-> copper chlorate + hydrogen
Naming salts
Hydrochloric acid produces chlorate HCl
Sulfuric acid produces sulphates H2SO4
Nitric acid produces nitrites HNO3
Acids reacting with metal oxides
Acid + metal oxide -> metal salt + water
Eg
Sulfuric acid + copper oxide -> copper sulphate +water
What is a ion
An ion as an atom which has gained or lost an electron
Positive has lost
Negative has gained
What is neutralisation
An acid reacts with a base to produce a neutral substance or other why round
acid + base/ alkali
Acid+base/alkali-> salt +water
H+ +OH- -> H2O
Naming salts
The first word is taken from the metal in the alkali second word by acid
Eg sodium hydroxide + hydrochloric acid-> sodium chloride + water
Strong vs week acids
A strong acid fully dissociates in water
A week acidic partially dissociates in water
Acid reacts with metal
Acid+metal-> metal salt+ hydrogen
Acid reacts with metal oxide
Acid+metal oxide-> metal salt + water
Eg nitric acid + sodium hydroxide -> sodium nitrite + water
Acid and metal carbonate
Acid+ metal carbonate -> metal salt+ water+ carbon dioxide
Eg hydrochloric acid + calcium carbonate. -> calcium chloride +water + carbon dioxide
Soluble salts practical
Use a measuring cylinder to pour dilute Sulfuric acid into a beaker warm the acid don’t don’t boil using a Bunsen burner add one spatula of copper carbonate powder to the acid and star until dissolved with the glass rod. Add more copper carbonate till it is saturated and excess poor solutions through a funnel with filter paper to remove un dissolved copper carbonate. Collect in a conical flask put the filter in evaporating basin and warm solution using Bunsen burner until half of it has evaporated leave the Bunson in a warm room overnight to let crystal salt form then Pat dry to remove moisture.
Titration practical
Fill Conical flask with 25 cm³ of hydrochloric acid and put a couple drops of indicator clamp The burette to clamp stand fill the burette with sodium hydroxide till the zero point using a funnel, put the white tile below the burette and place the conical flask on top so you can clearly see it as it neutralises, add small amounts of sodium hydroxide at a time by rotating the burette top swirl and repeat till neutralises/turns clear, repeat practical until get concordant result.
Looking at burette see how much acid is used ,this will be exact volume of sodium hydroxide that reacts with 25 cm³ of hydrochloric acid .
What is an ionic compound
A metal and non metal which metal has given electrons to non metal to make full outer shell
What is OIL RIG
Oxidation is lose reduction is gain
Why does electrolysis only work in molten or dissolved in water/aqueous state?
As ions are not free to move
What is electrolysis?
Electrolysis is the process by which molten ionic substances are broken down into a smaller substance using an electric current.
What forms at the cathode and what forms at the anode?
Cathode is negative so positive metal ion is attracted ( cation)
Anode is positive so negative non metal is attracted (anion)
How is aluminium oxide electrolysis?
The ore is known as bauxite and contains a lot of iron oxide impurities the first step in the process is to extract aluminium oxide from bauxite, the aluminium oxide is made molten however this has a melting point of 2050° C to save energy molten cryolite is added (A catalyst) this reduces the melting point and mixture can be electrolysed at 850° C.
