If you mix $50 \text{ cm}^3$ of HCl with $50 \text{ cm}^3$ of NaOH, the total mass ($m$) you use in the equation is , not 50. Many students lose marks on Worksheet 2 by forgetting to add the volumes together. Challenge 2: The Exothermic Sign Convention Enthalpy change ($\Delta H$) is negative for exothermic reactions and positive for endothermic reactions. However, the heat energy calculated ($q$) is always positive because energy is conserved.
For A-Level Chemistry students, few topics bridge the gap between theoretical math and physical reality quite like thermochemistry. Among the most popular resources used in classrooms across the UK and beyond are the worksheets provided by Chemsheets. Specifically, "Calorimetry Worksheet 2" is a rite of passage for students moving beyond basic enthalpy definitions into complex calculations.
Unless stated otherwise, assume the density of aqueous solutions is $1 \text{ g cm}^{-3}$. This means $1 \text{ cm}^3$ of solution has a mass of $1 \text{ g}$.