Chemical Changes

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Explain the process of oxidation?
In oxidation reactions a substance will lose electrons and often gains oxygen molecules
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Explain the process of reduction?
In reduction reactions a substance will gain electrons and often loses it's oxygen molecules
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Name all the elements above carbon on the reactivity series?
Potassium, sodium, calcium, magnesium and aluminium
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Name all elements from the reactivity series in order?
Potassium, sodium, calcium, magnesium, aluminium, carbon, zinc, iron, tin, lead, hydrogen, copper, silver, gold and platinum
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Name all the elements below carbon on the reactivity series?
Zinc, iron, tin and lead
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Name all the elements below hydrogen on the reactivity series?
Copper, silver, gold and platinum
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What is produced when a metal reacts with a acid?
A metal salt is formed along with hydrogen gas
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Explain what a displacement reaction is?
A displacement reaction is when a more reactive metal displaces or takes the place of a less reactive metal from a solution of it's salt
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How are metals that are less reactive than carbon extracted? (iron)
Metals like iron which are less reactive than carbon can be extracted from iron oxide by heating it with carbon, which causes carbon to displace the iron in the reaction
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What happens to substances when they dissolve in water?
When substances dissolve in water, they dissociate into their individual ions
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What makes a solution alkaline?
Hydroxide ions (OH) in an aqueous solution cause the solution to become alkaline
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What makes a solution acidic?
Hydrogen ions (H) in an aqueous solution cause the solution to become acidic
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Name two indicators that can be used to determine whether a solution is alkali or acidic?
Universal indicator and litmus
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Describe what happens in a neutralisation reaction?
Alkalis contain hydroxide ions where as acids contain hydrogen ions when an acid and a alkali react with each other, the hydroxide and hydrogen ions react to form water which neutralises the pH level of the solution as water has a pH of 7
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What is a soluble base?
A soluble base is an alkali
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What are acids neutralised by?
Acids are neutralised by bases i.e alkalis and metal oxides/carbonates
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How can soluble salts be made?
Soluble salts can be made by reacting acids with insoluble bases such as metal oxides, metal hydroxides and metal carbonates
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What makes an acid 'strong'?
To be 'strong' an acid must be completely ionised in water, having a higher concentration of hydrogen ions in a solution makes the solution more acidic
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Define ionised
When all atoms or molecules in a substance have been converted into ions
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What does the pH of a solution measure?
The pH of a solution is a measure of the concentration of hydrogen ions
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What is meant by a 'concentrated' and a 'dilute' acid?
An acid that has a high concentration of hydrogen ions is referred to as 'concentrated' where as a solution that contains less hydrogen ions is referred to as a 'dilute' solution
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What is electrolysis?
Electrolysis is the use of an electrical current to break down compounds containing ions into singular elements
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Define electrolyte
Electrolyte is the substance being broken down during electrolysis
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What happens during electrolysis?
During electrolysis negatively charged ions move to the anode, while positively charged ions move to the cathode
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Define cathode
The cathode is the negative electrode which attracts positively charged ions
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Define anode
The anode is the positive electrode which attracts negatively charged ions
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What is electrolysis used for?
Electrolysis is used to separate ionic compounds into elements
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Define redox reaction
A redox reaction is when both oxidation and reduction occur i.e electrolysis
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How are metals that are more reactive than carbon extracted?
Metals that are more reactive than carbon are extracted by electrolysis
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Define cryolite
Cryolite is a substance that lowers the melting point of aluminium oxide so that less energy is required for the electrolysis reaction
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How is aluminium obtained from aluminium oxide?
Electrolysis
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Name 1 disadvantage of electrolysis and a solution? (aluminium)
Electrolysis requires lots of heat and electrical energy therefore it is expensive, in the extraction of aluminium from aluminium oxide, cryolite is used which lowers the melting point of aluminium meaning less energy is used, makes process cheaper
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In electrolysis, when ionic compounds are in a aqueous solution, what substances are formed at the cathode?
Either hydrogen is produced (if the metal is more reactive than hydrogen) or the metal is produced (if the metal is less reactive than hydrogen)
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In electrolysis, when ionic compounds are in a aqueous solution, what substances are formed at the anode?
Either oxygen is produced (unless the solution contains halide ions) or (if halide ions are present), then the halogen is produced
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Describe the process of electrolysis when aqueous solutions are used?
As water is present; water molecules break down to form hydroxide ions which are attracted to the anode and hydrogen ions which are attracted to the cathode
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In the electrolysis of sodium chloride what is found or released at either electrode?
At the cathode, Hydrogen is released, At the anode Chlorine gas is released
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Other cards in this set

Card 2

Front

Explain the process of reduction?

Back

In reduction reactions a substance will gain electrons and often loses it's oxygen molecules

Card 3

Front

Name all the elements above carbon on the reactivity series?

Back

Preview of the front of card 3

Card 4

Front

Name all elements from the reactivity series in order?

Back

Preview of the front of card 4

Card 5

Front

Name all the elements below carbon on the reactivity series?

Back

Preview of the front of card 5
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