Hess Law cycles - An introduction - covers construction, vectors and different types

This is a lesson for A level chemistry where students are introduced to Hess Law through the topic of vectors that they would have learned at GCSE. The lesson starts with a GCSE recap on vectors then moves into discussing that some enthalpy changes reactions cannot be calculated or are difficult to calculate and so alternative reactions are used. Students then learn that the exams require them to use a few types of enthalpy change to calculate an unknown enthalpy change. These are bond enthalpies, enthalpy of combustion and enthalpy of formation. Students are told how to draw the arrows. Please note that this a very difficult topic for all students and do not assume that the lesson can be rushed for the brightest students. Please rate this resource and leave feedback.