The Relationship Between a Metals Rank in a Reactivity Series and Enthalpy Measurement

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the reactions:

Ca + 2HCl --> CaCl2 + H2

Fe+ HCl = FeCl3+ H2

CU + HCl = CUCl2 + H2

Al + HCl = AlCl + H2

Zn + HCl = ZnCl2 + H2

By the law of conservation the total energy of a system will not change. Therefore the energy that leaves the metal that is reacting with the HCL will be transferred to the HCL. The change in the temperature of the HCL at the end of the reaction is how much heat the metal lost.

It is theorized that the higher a metal is in the reactivity series the more likely that when it reacts it will have a large change in enthalpy. This is because more reactive metals have a greater tendency to loose electrons ( form positive ions). Certain metals release more energy when reacting than others. When atoms lose their electrons, they give them away with different force. The metal higher on the reactivity series will push away its electrons with more force, causing the other element to take its electrons. It is theorized that the more force the electrons are pushed with the more drastic the change in temperature of the reaction. (Making Electricity)

The reaction between the metals and the HCL will be exothermic (releases heat into the surroundings). In these reactions the products have a smaller amount of enthalpy when compared to the reactants. This is because the energy that is needed to break the bonds of the metals is less than the energy released when the products are created.