Chemistry Flashcards
What is a physical change?
.Experience changes physically
.Shape, size, volume, appearance
and state without making a new substance
Can be reversed
The same element or compound exists before and after
The chemical composition remains the same
What is a chemical change?
.The atoms of one or more substances are recombined or rearranged
to form a new substance
.The chemical properties of the substance change and it is transformed
into a different substance with a different chemical composition
. CHANGE IN COLOUR, TEMP, FORMATION OF BUBBLES, SMELL
CANNOT BE REVERSED
The Law of Conservation of Mass?
The total mass of reactants must equal the total mass of the products.
What is combustion?
burned fuel that releases energy
What is a fuel?
The substance which is burned to release energy
What is oxidation?
A substance gains oxygen atoms
When does combustion happen and why is it useful?
When anything is burning
We end up getting heat
We can burn stuff
What is the fire triangle?
All the components needed for a fire
FUEL OXYGEN HEAT
Name some fuels?
Coal
Wood
Hydrogen
Wax
Gas (methane)
What releases energy
respiration
burning fuels
combustion
nuclear fission
fusion
oxidation
What is an Exothermic Reaction and what happens in one?
A reaction that GIVES OUT energy to the surroundings
The temperature rises
This is because reacting particles have transferred chemical potential energy to the surrounding
What is an Endothermic Reaction and what happens in one?
A reaction that TAKES IN energy from surroundings
The temperature drops
This is because reacting particles have taken in chemical potential energy from the surrounding
What is thermal decomposition?
Breaking something down by heating
What is a solute solution and solvent?
Solute: the substance being dissolved
Solvent: the original liquid that is mixed
Solution: A mixture of the solvent and solute
