Energy Changes LO: Describe what happens in endo and exo thermic processes (D) Explain how you can tell if a reaction is endothermic (C) Investigate energy changes in a reaction (B) Make conclusions about energy changes and what happens during reversible reactions (A/A*) Starter What do you think the word Exothermic means ? Hint: Break the word up into smaller bits to see what they mean.

Definitions Exothermic = heat given out in a reaction. (gets hotter) Endothermic = heat taken in during a reaction. (gets colder or needs a bunsen)

Practical SAFETY – WEAR GOGGLES AT ALL TIMES. REPORT & CLEAN ALL SPILLS AND BREAKAGES. STAND UP. DO NOT RUN.

Practical -Measure 25cm 3 copper sulphate into the calorimeter. -Measure the temperature every minute for 2 mins. -Quickly add 1g of Zinc powder and stir. -Take the temperature constantly every minute for 8 mins. Time (mins) Temperature ( o C) Added zinc

After an exothermic reaction is there more or less energy in the chemicals afterwards ? After an endothermic reaction is there more or less energy in the chemicals afterwards ?

Review of results Draw a diagram that shows your experiment. Draw a graph of the results.

Hydrated copper sulphate copper sulphate + water Endothermic to make this reaction go from left to right. The reaction the other way is Exothermic. For reactions to go in reverse the reaction is the opposite for heat. Exo becomes Endo Endo becomes Exo ENDO EXO

N H 2 2 NH 3 EXO ENDO

Questions