GCSE Chemistry: Chemical Changes, Reactions, and Electrolysis

What is the reaction of metals with oxygen called?

Oxidation reactions

What do metals form when they react with oxygen?

Metal oxides

What is the definition of reduction in terms of oxygen?

Loss of oxygen

What is the definition of oxidation in terms of oxygen?

Gain of oxygen

How are metals arranged in the reactivity series?

In order of their reactivity based on their tendency to form positive ions

Which metals are more reactive: potassium or copper?

Potassium

What happens when a more reactive metal displaces a less reactive metal?

The more reactive metal can displace the less reactive metal from a compound.

How can metals less reactive than carbon be extracted?

By reduction with carbon

What does the acronym OIL RIG stand for?

Oxidation Is Loss, Reduction Is Gain (of electrons)

What is produced when acids react with metals?

A salt and hydrogen

What type of reaction occurs when acids react with metals?

Redox reactions

What is the general equation for the reaction of an acid with a metal?

Acid + Metal -> Salt + Hydrogen

What is produced when an acid is neutralized by an alkali?

A salt and water

What is the equation for the neutralization of an acid by an alkali?

Acid + Alkali -> Salt + Water

What do acids produce when they react with metal carbonates?

Salts, water, and carbon dioxide

What type of salts does hydrochloric acid produce?

Chlorides

What type of salts does nitric acid produce?

Nitrates

What type of salts does sulfuric acid produce?

Sulfates

What is the first step in making soluble salts from acids?

Add the chosen solid insoluble substance to the acid.

How do you know when the acid has been neutralized during salt production?

Excess solid sinks to the bottom.

What is the process called when you evaporate water to obtain salt crystals?

Crystallisation

What do acids produce in aqueous solutions?

H+ ions

What do alkalis produce in aqueous solutions?

OH- ions

What is the pH range of the pH scale?

0 to 14

What pH value indicates a neutral solution?

pH 7

What pH value indicates an acidic solution?

pH < 7

What pH value indicates an alkaline solution?

pH > 7

What is the ionic equation for neutralisation?

H+(aq) + OH-(aq) -> H2O(l)

What is the purpose of titration in chemistry?

To measure the volumes of acid and alkali solutions that react with each other.

What is the first step in carrying out a titration?

Wash the burette using dilute hydrochloric acid and then water.

How much acid should be filled in the burette for titration?

100 cm³

How much alkali is typically added to the conical flask in a titration?

25 cm³

What indicator is commonly used in titrations?

Phenolphthalein

What color does phenolphthalein turn in an alkaline solution?

Pink

What is the titre in a titration?

The volume of acid needed to exactly neutralise the alkali.

What is the conversion factor between dm³ and cm³?

1 dm³ = 1000 cm³

What is the relationship between moles and grams for a substance?

One mole of a substance in grams is the same as its relative atomic mass in grams.

What characterizes a strong acid?

It is completely ionised in aqueous solution.

Give an example of a strong acid.

Hydrochloric acid, nitric acid, or sulfuric acid.

What characterizes a weak acid?

It is partially ionised in aqueous solution.

Give an example of a weak acid.

Ethanoic acid, citric acid, or carbonic acid.

How does the strength of an acid relate to its pH?

Stronger acids have lower pH values.

What happens to the H+ concentration when pH decreases by one unit?

The H+ concentration increases by a factor of 10.

What is the process of electrolysis?

Breaking down a substance into elements by passing a current through it when it is molten or in solution.

What happens to positively charged ions during electrolysis?

They move to the negative electrode (cathode).

What happens to negatively charged ions during electrolysis?

They move to the positive electrode (anode).

What is produced at the cathode during the electrolysis of molten ionic compounds?

The metal.

What is produced at the anode during the electrolysis of molten ionic compounds?

The non-metal.

What is required to extract metals more reactive than carbon?

Electrolysis of molten compounds.

What is the role of cryolite in the electrolysis of aluminium oxide?

It lowers the melting point of aluminium oxide, making the process cheaper.

What are the order of reactivity series

Potassium

Sodium

Lithium

Calcium

Magnesium

Aluminium

Carbon

Zinc

Iron

Hydrogen

Copper