WHAT IS A CHEMICAL REACTION?
A chemical reaction is a process in which one or more substances are combined and leads to the chemical transformation of one substance into another.
HOW DO WE KNOW WHEN CHEMICAL REACTIONS ARE HAPPENING?
CHANGE OF COLOUR
is a sign of a chemical reaction.
When metal rusts, it turns into a reddish-brown colour. That's a chemical reaction!
TEMPERATURE CHANGE
Chemical reactions involve a transfer of energy. When something becomes warm, energy is being released during the reaction. In other reactions, energy is absorbed making it colder.
PRECIPITATE FORMATION
A precipitate is something solid that is created from a reaction when mixing liquids.
LIGHT EMISSION
When you crack a glow stick to make it light up, a chemical reaction is happening right there!
GAS IS PRODUCED
When two liquids are mixed and bubbles are created, it usually means that a gas has been produced.
WHAT AFFECTS THE RATE OF A CHEMICAL REACTION?
TEMPERATURE
Increasing the temperature will increase the rate of reaction. By increasing the temperature, the particles have more energy to move around more often. A lower temperature means the reaction of the chemical will be slower.
SURFACE AREA
The surface area can affect the reaction of the experiment. The more surface area that the chemical is touching, the more reaction will happen in the experiment so it will finish faster. Less surface area in contact with the chemical will have less reaction and will last longer.
CONCENTRATION
Increasing the concentration of one or more reactant will increase the rate of reaction. A higher concentration means more bumps between particles and more energy will be created.
A CATALYST?
A Catalyst is a chemical that can speed up a reaction by adding it into the experiment without being consumed by other chemicals. This could also provide a different result for the experiment.