Required practical 2: measure an enthalpy change.

In the subtopic AS required practical activities, this AQA A-Level Chemistry 7405 learning objective focuses on required practical 2: measure an enthalpy change. It belongs to AS practical skills and required practical activities, so revision should stay anchored to this exact subtopic rather than drifting into a generic GCSE-level chemistry summary. Approved keywords to use include required practical, enthalpy. Enthalpy change. means the heat change associated with a chemical reaction at constant pressure, measured in joules or kilojoules Avoid the mistake of students often forget to account for the specific heat capacity of the solution when calculating the enthalpy change, leading to inaccurate results; instead, to fix this, remember to use the formula q = mcΔT, where q is the heat energy, m is the mass of the solution, c is the specific heat capacity, and ΔT is the change in temperature. Substitute the values correctly and ensure to include units in your final answer. For example, if you have 100 g of water (m = 100 g), with a specific heat capacity of 4.18 J/g°C (c), and a temperature change of 10°C (ΔT), the calculation would be: q = 100 g × 4.18 J/g°C × 10°C = 4180 J. Thus, the enthalpy change is 4180 J For exam answers, always ensure to use a calorimeter for accurate enthalpy change measurements. Record the initial and final temperatures carefully