The energy that is stored in the bonds of chemical compounds such as atoms and molecules
Energy changes in chemical reactions
1. Increase in overall energy of the system
2. Decrease in overall energy of the system
3. Change in temperature
4. Change in light emission
Chemical energy is the source of most of the energy that humans need to function
Humans release this chemicalenergy during digestion and use it to power systems inside the body
Plants store chemical energy in carbohydrates formed during photosynthesis
Energy changes are very important in chemistry because almost all reactions involve a change in energy
Whenever a chemical reaction takes place between reactants to form products, there is always an energy change usually in the form of heat
Energy change in a chemical reaction
Difference in the amounts of stored chemical energy between the reactant and the product particles
Interactions between particles
Cooling effects
Heating effects
Activation of instant cold pack and hot pack
1. Change in temperature
2. Dissolving of a solid substance (salt) in water
3. Chemical reaction
These packs contain a mixture of chemicals that react together to create heat and cold
Chemical reaction
1. Breaking of bonds in the reactants
2. Forming of bonds in the products
In the given examples of cold and hot packs, energy is absorbed to break bonds, and energy is released when bonds are formed during the process of dissolving
Chemical reactions provide electricity which is the result of interactions between ions
