C5- Chemical changes Flashcards
State the reactivity series
Potassium, sodium, lithium, calcium, magnesium, aluminium, carbon, zinc, iron, tin, lead, hydrogen, copper, silver, gold.
What metals fizz and release hydrogen with water?
Potassium, sodium, lithium, calcium
What metals have a very slow reaction with water?
Magnesium, aluminium, zinc, iron
What metals react only with steam, not water?
Tin, lead
What metals don’t react with water at all?
Copper, silver, gold
What metals explode with dilute acid?
Potassium, sodium, lithium
What metals fizz, produce hydrogen and form a salt with dilute acid?
Calcium, magnesium, aluminium, zinc, iron
What metals react with warm dilute acid?
Tin, lead
What metals don’t react with dilute acid?
Copper, silver, gold
What is the general rule for a displacement reaction
A more reactive metal will displace a less reactive metal from it’s compound
What does an ionic equation show
Only the atoms and ions that change in a reaction
Oxidation
Oxygen?
Electrons?
Gains oxygen
Loses electrons
Reduction
Oxygen?
Electrons?
Loses oxygen
Gains electrons
Metal ores definition
Rocks that contain enough metal compounds to make it economical to extract the pure metal
3 factors when deciding to extract a metal
-How easy it is to extract
-How much metal the ore contains
-Demands for a metal
What metals are found in the Earth in their natural state and why?
Gold and silver because they are so unreactive
Extracting metals using carbon, products?
Metal and carbon dioxide
How are metals that are more reactive than carbon extracted?
By electrolysis
What is a salt?
A compound formed when the hydrogen in an acid is wholly or partially replaced by metal ions
How can salts be made?
By reacting an acid with a metal that is more reactive than hydrogen but not dangerous
What does a reaction between a metal and acid produce?
A salt and hydrogen
What type of reaction is between a metal and an acid and why?
A redox reaction
The metal atoms lose electrons and the hydrogen ions gain electrons
What does a reaction between an acid and a base produce?
What is this reaction called?
A salt and water
A neutralisation reaction
Key fact of the charges on a salt?
The sum of charges on a salt equal zero
How to make pure copper sulfate crystals from sulfuric acid and copper oxide.
-Gently heat 30cm3 of sulfuric acid in beaker over bunsen burner
-Add 2 spatulas of copper oxide, stir, ensure it is in excess
-Filter the solution through filter paper
-Pour solution in evaporating basin, gently heat until most of liquid has evaporated
-Leave rest of liquid to evaporate slowly, larger crystals and gently dry
What does a reaction between an acid and alkali produce?
What is this called?
A salt and water
Neutralisation
Neutralisation balanced symbol equation
H+ + OH- —–> H2O
How to collect a pure, dry salt from a reaction with an acid and alkali
Carry out a titration (with indicator) to find the exact volume of acid needed. Use same volume of acid with alkali (no indicator). Crystallise
What does a reaction between an acid and a carbonate produce?
A salt, water and carbon dioxide
Acid
A substance that releases hydrogen ions (H+) in solution
Base
A substance that neutralises an acid (including alkalis)
Alkali
A soluble base- all alkalis form OH- ions in solution
2 key ways to show how acidic or alkaline a solution is
What number shows acid, alkali and neutral?
pH scale
universal indicator
Acid=less than 7
Alkali=greater than 7
Neutral=7
Difference between strong and weak acids?
Strong- ionise fully in water
Weak- partially ionises in water
What happens to the H+ ions when the pH decreases by 1 unit?
The H+ ion concentration increases by a factor of 10
