How to Demonstrate Bond Energy

A difficult concept for many students to understand is the energy involved in breaking and forming bonds. A hydrate is a substance that has water bonded to it. In order to dehydrate you must add energy (endothermic) to break the bond to water. When hydrating you are forming a bond to water and will release energy (exothermic). This visual demonstration reinforces the concept.

Copper (II) Sulfate Penta Hydate is heated and water is driven of (bonds broken)

Water is add (bonds form) heat is then released

Exothermic to make bonds
endothermic to break bonds



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    2 Discussions


    11 years ago on Introduction

    ahahah my chem teacher did this waaay back when i was in high school.. but he got us to make the anhydrous form, then put a little bit (spatula tip) on our hands and add some water. those who put more water on didn't get such a shock, because it dissipated the heat better :) probably not really safe, but he made sure nobody took too much to put on their hand (and heck, i'm still doing chemistry more than 10 years later...)