Reactivity 1.1.1 - Chemical reactions involve a transfer of energy between the system and the surroundings, while total energy is conserved.

• Understand the difference between heat and temperature.

Guidance

Tools and links

• Structure 1.1 - What is the relationship between temperature and kinetic energy of particles?

Reactivity 1.1.2 - Reactions are described as endothermic or exothermic, depending on the direction of energy transfer between the system and the surroundings.

• Understand the temperature change (decrease or increase) that accompanies endothermic and exothermic reactions, respectively.

Guidance

Tools and links

• Tool 1, Inquiry 2 - What observations would you expect to make during an endothermic and an exothermic reaction?

Reactivity 1.1.3 - The relative stability of reactants and products determines whether reactions are endothermic or exothermic.

• Understand the difference between heat and temperature.

Guidance

Tools and links

• Structure 1.1 - What is the relationship between temperature and kinetic energy of particles?

Reactivity 1.1.4 - The standard enthalpy change for a chemical reaction, ΔH^⦵, refers to the heat transferred at constant pressure under standard conditions and states. It can be determined from the change in temperature of a pure substance.

• Apply the equations Q = mcΔT and ΔH = − Q/n in the calculation of the enthalpy change of a reaction.

Guidance

• The units of ΔH^⦵ are kJ mol^–1.
• The equation Q = mcΔT and the value of c, the specific heat capacity of water, are given in the databooklet.

Tools and links

• Tool 1, Inquiry 1, 2, 3 - How can the enthalpy change for combustion reactions, such as for alcohols or food, be investigated experimentally?
• Tool 1, Inquiry 3 - Why do calorimetry experiments typically measure a smaller change in temperature than is expected from theoretical values?