Topic 1 - 1.1 - Chemical Reactions Flashcards
What is a chemical reaction?
When one or more substances react together to produce one or more new chemical substances.
Define the rate of reaction
It is a measure of how fast the reactants are being used up and how fast the products are made.
What are reactants and products?
Reactant - Substances changed by the chemical reaction
Products - Substances produced by the chemical reaction
Name 4 signs of a chemical reaction
- Colour change
- Effervescence
- Precipitation
- Energy Change
Describe colour change as a sign of a chemical reaction
It can happen when a compound is broken down by heating it (thermal decomposition)
Describe effervescence as a sign of a chemical reaction
Happens when a reaction inside a liquid produces bubbles of gas
Describe precipitation as a sign of a chemical reaction
When certain liquids react together to form an insoluble solid
What is an exothermic reaction?
energy change
Heat energy is RELEASED because reactant energy is more than product energy
What is an endothermic reaction?
energy change
Heat energy is ABSORBED because reactant energy is more than product energy
