physical chemistry

• Chemical reactions where heat energy is given out are exothermic, while those where heat energy is taken in are endothermic
• Simple calorimetry experiments can be described for reactions like combustion, displacement, dissolving, and neutralisation
• Heat energy change can be calculated from a measured temperature change using the expression Q = mcΔT
• The molar enthalpy change (ΔH) can be calculated from the heat energy change Q
• Practical investigation can involve temperature changes accompanying reactions like salts dissolving in water, neutralisation reactions, displacement reactions, and combustion reactions
• Experiments can be conducted to investigate the effects of changes in surface area of a solid, concentration of a solution, temperature, and the use of a catalyst on the rate of a reaction
• Particle collision theory can explain the effects of changes in surface area of a solid, concentration of a solution, pressure of a gas, and temperature on the rate of a reaction
• A catalyst is a substance that increases the rate of a reaction but remains chemically unchanged at the end of the reaction
• A catalyst works by providing an alternative pathway with lower activation energy
• Practical investigations can include changing the surface area of marble chips and the concentration of hydrochloric acid to observe the rate of reaction between them
• The effect of different solids on the catalytic decomposition of hydrogen peroxide solution can be investigated
• Some reactions are reversible, indicated by the symbol ⇌ in equations
• Reversible reactions like the dehydration of hydrated copper(II) sulfate and the effect of heat on ammonium chloride can be described