lesson 2

• Nature of reactant refers to reaction rate variation is dependent on which substances are

  reacting.
• Reactions tend to be slow when covalent bond formation

  takes place between the molecules and when large molecules are formed.
• When the concentration of the reactants increases, the frequency of

  the molecules colliding increases, striking each other more frequently.
• Molecules at a higher temperature have more thermal energy and

  collision frequency is greater at higher temperatures.
• Catalysts are substances used to facilitate reactions but remain

  chemically unchanged afterwards.
• Enthalpy is a thermodynamic property of a system.
• Enthalphy refers to the sum of

  the internal energy added to the product of the pressure and volume of

  the system.
• Enthalpy is denoted as H
• BTU means (British

  Thermal Unit.)
• CHARACTERISTICS OF ENTHALPHY

  • used to calculate the heat of reaction of a chemical process.

  *used to measure heat flow in

  calorimetry