Pure Substances, Mixtures, and Catalysts
This page covers the differences between pure substances and mixtures, introduces the concept of concentration, and explains the role of catalysts in chemical reactions.
Pure substances have distinct melting and boiling points, while mixtures melt and boil over a range of temperatures.
Highlight: The sharp melting and boiling points of a substance can be used to determine its purity.
Concentration is defined as a measure of how much solute solid is dissolved in a solvent liquid.
Definition: Concentration is the amount of solute dissolved in a given amount of solvent.
The page provides a detailed explanation of catalysts:
Definition: A catalyst is a substance that increases the rate of a chemical reaction without being consumed in the process.
Key points about catalysts:
- They speed up reactions without being used up
- Provide an alternative reaction route with lower activation energy
- Widely used in chemical processes to increase product yield
- Enzymes are biological catalysts largeproteinmolecules
Example: Enzymes in the human body act as catalysts for various biological reactions, such as the breakdown of food during digestion.
The page also introduces the concepts of exothermic and endothermic reactions:
- Exothermic reactions release energy
- Endothermic reactions absorb energy
Vocabulary: Activation energy is the minimum amount of energy required for a chemical reaction to occur.
