C4 - Chemical Changes

What happens to the reactivity of elements as you go down group 1?

They get more reactive.

Define displacement reaction

A reaction where a more reactive element takes the place of a less reactive element to form a compound

Which is more reactive - potassium or sodium?

Potassium.

Which is more reactive - hydrogen or carbon

Carbon

Which is more reactive - magnesium or aluminium

Magnesium.

What metals are less reactive than hydrogen?

Copper, silver, gold, platinum (jewellery metals)

Define an ore.

metal compound found in a rock.

Define electrolyte.

A liquid or solution containing an ionic compound (can conduct electricity)

If the electrolyte is soluble how would you make it a liquid?

Dissolve it in water to make it aqueous

If the electrolyte is insoluble how would you make it a liquid?

Melt it to make it molten

What is the name of the positive electrode?

Anode.

What is the name of the negative electrode?

Cathode.

Define electrolysis

Splitting up with electricity

Are ions at the anode being oxidised or reduced?

Oxidised

Are ions at the cathode being oxidised or reduced?

Reduced.

The pH of the solution is 14

What is the colour of the universal indicator?

Dark Purple

What is formed at the cathode?

Hydrogen unless there is a metal more reactive which is then produced instead

What is formed at the anode?

Oxygen unless there is a halide present which would then release as a halogen

Define acid

A substance that dissociates in water to form H+ ions

Define base

Any substance that will neutralise an acid

Define alkali

A soluble base that releases OH- ions in water

Ionic equation for neutralisation:

H+ + OH- -> H2O

Acid + alkali 🡢

salt + water

Acid + metal 🡢

salt + hydrogen

Acid + Metal Carbonate 🡢

salt + water + carbon dioxide

Acid + Metal Oxide 🡢

salt + water

Define strong acid

Fully dissociate in water (100% of H+ ions released)

Define weak acid

partially dissociates in water

Define acid concentration

The measure of how many moles of acid are dissolved in a given volume of water.

As hydrogen ion concentration increases by a factor of 10 ...

the pH value decreases by 1

What are two ways a metal can be extracted from its ore.

Reduction with carbon and electrolysis

Why are different methods used to extract metals from ores?

Depends on the reactivity of the metal. If its more reactive than carbon then electrolysis has to be used.

Name a strong acid

HCl, NO3 -

Nitric acid formula

HNO3

Nitrate ion charge

NO3 -

Sulfuric acid formula

H2SO4

Sulfate ion charge

SO4 2-

What does the reactivity of a metal depend on?

It's ability to form a positive ion

What is cryolite used for?

To lower the melting point of the aluminium oxide

What colour is phenolphthalein in acidic solutions?

Colourless

Reactivity series pneumonic

please stop calling me a careless zebra instead try learning how copper saves gold

What pH indicator is red in acid and blue in alkaline solutions?

Litmus

What pH indicator is colourless in acidic solutions?

Phenolphthalein

What colour is phenolphthalein in alkaline solutions?

Pink

What type of reaction is it when an acid and a base react together?

Neutralisation

When metals react, do the atoms become positive or negative ions?

Positive

What group is the most reactive?

Group 1 (alkali metals)

acid + metal oxide

salt + water

acid + metal hydroxide

salt + water

acid + metal carbonate

salt + water + carbon dioxide

The general word equation for the reaction between a metal and an acid is:

Metal + acid ➔ salt + hydrogen

Why do we find pure gold in the ground, but not pure iron?

Gold is unreactive, so doesn't react with any other elements

Iron is reactive enough to react with oxygen so is oxidised to iron oxide

Why are forks covered in a silver coating?

Improve lifespan/appearance

Is this a strong or weak acid: hydrochloric acid?

Strong acid

Is this a strong or weak acid: nitric acid?

Strong acid

Is this a strong or weak acid: sulfuric acid?

Strong acid

Is this a strong or weak acid: ethanoic acid?

Weak acid

Is this a strong or weak acid: citric acid?

Weak acid

Is this a strong or weak acid: carbonic acid?

Weak acid

Reactivity series

Potassium

Sodium

Lithium

Calcium

Magnesium

Carbon

Zinc

Iron

Hydrogen

Copper

Why should you swirl the conical flask during the titration?

to evenly distribute the acid/alkaline

Do metals react more violently with water or acid?

acid

metal + acid ->

salt + hydrogen

metal + water ->

metal hydroxide + hydrogen

What two reactions produce hydrogen instead of water?

metal + water and metal + acid

acid + metal oxide ->

salt + water

acid + metal hydroxide ->

salt + water

acid + metal carbonate ->

salt + water + carbon dioxide

acid + insoluble base ->

soluble salt -> water