Chemistry End of Year

Burning fuels such as hydrocarbons is useful because it releases light and what kind of energy?

Heat energy

Oxidation reactions involve the loss of

electrons

What kind of reaction is being used to extract copper from its salt solution using the iron nail?

Displacement

What is a displacement reaction

Displacement reactions involve a more reactive element displacing a less reactive element from a compound.

When a hydrocarbon fuel is burned in a low oxygen environment, particulates may be released. What do we call these particulates?

Soot

During combustion what type of chemical reaction takes place?

Oxidation

What is reduction

Reduction is the loss of oxygen, or the gain of hydrogen.

What type of combustion will happen in a Bunsen burner when the flame is yellow?

Incomplete (there is not enough oxygen)

Zinc sulfate is produced by reacting zinc oxide with which substance?

sulfuric acid

What reactions involve 2 solutions reacting to form an insoluble product?

Precipitation

Name the product produced by the combustion of hydrogen

water

Reduction is the __________ of electrons.

gain

What is a Chemical reaction?

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

How do you know a reaction has taken place?

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 is the gain of oxygen, or the loss of hydrogen.

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

What is a carbonate

a salt of a carbonic acid

Examples of oxidation

Rusting, water