Physical and Chemical Change Flashcards
What is the differences between physical and chemical change
The difference is that in a physical change no new substance is formed, but in a chemical change there is one or more new substances
Evidence of chemical change
change in colour
change in temperature
production of light or sound
disappearance of a solid
formation of a new solid
formation of a new gas – may be indicated by fizzing or a new odour
What is the reactants and products in a chemical equation
The reactants are the substances with which you begin the reaction.
The products are the substances made as a result of the reaction.
How does Particle size affect the rate of chemical reaction
The greater the surface area, the higher the chance of collisions, thus the faster the rate of reaction. The smaller the particle size the faster the reaction.
How does Temperature affect the rate of chemical reaction
When a reaction is heated, energy is transferred to the reactants, more particles have energy greater than the activation energy. Therefore, more successful collisions
How does Concentration affect the rate of chemical reaction
If the concentration of reactants is increased, there are more reactant particles moving together. There will be more collisions and so the reaction rate is increased. The higher the concentration of reactants, the faster the rate of a reaction will be.
How does Catalysts affect the rate of chemical reaction
A catalyst is a substance that can be added to a reaction to increase the reaction rate without getting consumed in the process. Catalysts typically speed up a reaction by reducing the activation energy or changing the reaction mechanism.
