Chemistry types of reactions

What is a Chemical reaction?

A reaction in which atoms break existing bonds and form new ones to create different molecules.

Observations in a chemical reaction

changes in colour, the formation of a gas (indicated by bubbles), and temperature changes.

(s)

solid

(l)

liquid

(g)

gas

(aq)

aqueous solution

The law of Conservation of Mass

the total mass of reactants in a chemical reaction is equal to the total mass of products

Fuel

Any compound which has stored energy.

What is needed for complete combustion?

A hydrocarbon and oxygen

Why does incomplete combustion occur?

There is not enough oxygen

Complete combustion equation

Hydrocarbon + oxygen → Carbon dioxide + water

How do you detect water vapour?

Cobalt (lll) chloride paper changes colour from blue to pink when exposed to moisture

How do you detect carbon dioxide?

Pump it into limewater and if it turns cloudy it has CO2

Products of incomplete combustion

Carbon (soot) and carbon monoxide

Hazards of incomplete combustion in an enclosed space

carbon monoxide poisoning

Fire triangle

Oxygen, heat, fuel

How can you put out a fire using the fire triangle

Deprive it of fuel, heat or oxygen

What is oxidation?

when oxygen is added to a chemical in a reaction

oxidation equation

metal + oxygen → metal oxide

What happens to the mass of the metal when it is oxidised?

It generally goes up as new oxygen atoms join the chemical

What is Thermal decomposition?

Breaking something down with heat

Thermal decomposition word equation

metal carbonate → metal oxide + carbon dioxide

Why does thermal decomposition lead to mass decreasing?

carbon dioxide gets released and reduces the mass.

What is a carbonate?

A salt of a carbonic acid

general word equation for carbonate reactions

acid + carbonate → salt + water + carbon dioxide

Examples of acids

Hydrochloric acid, sulfuric acid, carbonic acid.

Which metal is the most reactive?

francium

which metal is the least reactive?

Gold

hydrogen test

Squeaky pop test

what products are formed in a reaction of a metal with an acid?

a salt and hydrogen

what is precipitation

A reaction in which substances in a solution are mixed and an insoluble product is made

What does soluble mean

Can dissolve in a liquid

what does insoluble mean

Doesnt dissolve in a liquid

how do you separate a solution with an insoluble solid?

Filter it

What is a nugget?

A pure lump of a precous metal

What is an ore?

A rock that contains a valuable metal

How do you extract a metal?

Displace it so the element is by itself

What does endothermic mean?

Takes in energy from the surroundings and becomes colder

What does exothermic mean?

Releases heat

Uses of endothermic reactions

Instant ice packs and fridges

uses of exothermic reactions

hand warmers and self heating cans

is combustion endothermic or exothermic

exothermic

is oxidation endothermic or exothermic

exothermic

is thermal decomposition endothermic or exothermic

endothermic