GCSE AQA Chemistry- Chemical changes

The gain of oxygen or the loss of electrons

What is oxidation?

The loss of oxygen or the gain of electrons

What is reduction?

Potassium, sodium, calcium, magnesium, aluminium, carbon, zinc, iron, tin, lead, hydrogen, copper, silver, gold, platinum

What is the order of the reactivity series?

How easily a metal loses electrons

What is meant by "reactivity"?

A metal salt and hydrogen

What is produced when a metal reacts with an acid?

A metal hydroxide solution and hydrogen

What is produced when the alkali metals react with water?

For comparison

Why does the reactivity series of metals often contain carbon and hydrogen?

A more reactive metal will displace the less reactive metal from its salt

What happens in a displacement reaction?

By reduction with carbon (heat then with carbon)

How can metals that are less reactive that carbon be extracted from their oxides?

Hydroxide (OH-)

What ions is found in all alkalis?

Hydrogen, H+

What ion is found in all acids?

The acidity or alkalinity is a substance

What is the pH scale a measure of?

7

What is a neutral pH?

Between 0 and 6 (Closer to 0, the stronger the acid)

What is the range of acidic pH?

Between 8 and 14 (Closer to 14, the stronger the alkali)

What is the range of alkaline pH?

Using a pH probe or universal indicator

How can we measure the pH?

Dyes that change colour depending on if they're in an acidic or alkaline solution

What is an indicator?

Red

What colour does litmus paper go in an acid?

Blue

What colour does litmus paper go in an alkali?

Acid + metal hydroxide = salt + water

What is the neutralisation equation for a acid and metal hydroxide?

H+ + OH- = H2O

What is the neutralisation equation for an acid and alkali reacting?

Acid + metal oxide = salt + water

What is the neutralisation equation for an acid and a metal oxide?

Acid + metal carbonate = salt + water + carbon dioxide

What is the neutralisation equation for an acid and a metal carbonate?

Metal name, name from acid

How do we name the salts in a neutralisation equation?

Chloride salts

What type of salt does hydrochloric acid produce?

Nitrate salts

What type of salts does nitric acid produce?

Sulphate salts

What type of salts does sulphuric acid produce?

The H+ ions are fully ionised in water

What is meant by a strong acid?

The H+ ions are not fully ionised in water

What is meant by a weak acid?

The concentration of the H+ ions in a solution

What ions does pH measure?

The concentration of hydrogen ions has increased or decreased by 10

What does a change of one unit in pH indicate?

The use of an electrical current to break down compounds containing ions into their elements

What is electrolysis?

What is the positive electrode during electrolysis?

The anode

What is the negative electrode during electrolysis?

The cathode

What are the negative ions called in electrolysis?

Anions

What are the positive ions called in electrolysis?

Cations

What happens at the cathode during the electrolysis of ionic substances?

The metal goes to the cathode because metals always loose electrons in ionic bonding and is reduced (gains electrons)

What happens at the anode during the electrolysis of ionic substances?

The non-metal element forms at the anode and is oxidised (looses electrons)

What would happen during the electrolysis of lead bromide?

The lead would form at the cathode and gain 2 electrons to form pure lead, the bromide would form at the anode as a gas and gain electrons

What happens in a redox reaction?

Both oxidation and reduction take place

What happens to compounds to be able to extract metals by electrolysis?

They are melted and cryolite is added to reduce melting point

What material is used as the electrodes during electrolysis for extracting metals?

Carbon

What happens during the electrolysis of aluminium oxide (metal extraction)?

The aluminium forms at the cathode and is reduced, the oxygen forms at the cathode and reacts with the carbon in the electrodes to form carbon dioxide

What happens at the cathode during electrolysis of aqueous solutions?

Hydrogen is produced at the cathode if the metal is more reactive than hydrogen

What happens at the anode during the oxidation of an aqueous solution?

Oxygen forms, unless a halide ion is present, the the halogen forms at the anode.

If a halogen forms at the anode during the electrolysis of an aqueous solution, what happens to the solution left behind?

It turns alkali because it is always the oxygen that from the OH- ions that forms so it is left in the solution causing it to be alkaline.