Flashcards in Topic 2 - (reactions) Deck (28)
What does the law of conservation of mass mean?
That mass is never lost or gained in chemical reactions
If the .......... is a gas, you will observe a mass increase
If the .......... is a gas, you will observe a mass decrease
What is combustion?
When a fuel reacts with oxygen to release energy
What are 3 things needed to make a combustion?
What is oxidation?
When a substance reacts and combines with oxygen
Combustion is a type of ............ reaction
What is the equation of rusting?
Iron + oxygen - iron oxide (rust)
What is iron oxide?
Take in heat
Which reactions are exothermic?
Neutralisation and oxidation
Which reactions are more common? Exothermic or endothermic?
Which reactions are also endothermic reactions?
Thermal decomposition reactions
What is a thermal decomposition reaction?
A reaction that uses heat to break down a substance into smaller molecules
What is an example of a thermal decomposition reaction?
CaCO3 - CaO + CO2
(Making lime from lime water!)
What do carbonates produce when they decompose?
Name 3 uses of thermal decomposition reactions
- Making lime from lime water
- Extracting Mercury
- Thermal cracking
What is a precipitation reaction?
A reaction in which a solid is made
What is the precipitate in a reaction?
What does the state symbol (aq) mean?
Dissolved into solution
What do reactions involve?
A transfer in energy
What is an example of a precipitation reaction? And what is the precipitate
Potassium iodide (aq) + lead nitrate (aq) - potassium nitrate (aq) + lead iodide (s)
Precipitate: LEAD IODIDE (s)
What is CaCO3?
What is iron oxide? ( FeO)
In a chemical reaction, WHY is there no change in mass?
Because you can’t create or destroy atoms
What can oxidation reactions be used to make?
Acids and bases