A student investigates the reaction between solid barium hydroxide octahydrate and solid ammonium chloride in a sealed vessel. The temperature of the mixture is monitored using a digital probe and is observed to decrease from 294.5 K294.5\text{ K}294.5 K to 261.2 K261.2\text{ K}261.2 K.
State the term used to describe this type of heat energy change.
Practise Edexcel GCSE Chemistry Heat energy changes in chemical reactions with exam-style questions for Foundation and Higher tier. 130 questions, matched to the Edexcel GCSE Chemistry (1CH0) specification and written in Paper 1 and Paper 2 style. Every question includes a full worked solution and mark scheme, so you can see where marks are awarded rather than just whether you got the answer right.
