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Thermal Decomposition of Metal Hydroxides Some metal hydroxides will thermally decompose to form a metal oxide and water (in the form of steam). The presence of water can be shown by adding a piece of blue cobalt chloride paper to the mouth of the a test tube during a decomposition reaction. The cobalt chloride paper will change from blue (dehydrated) to pink (hydrated). The general equation for the thermal decomposition of a metal hydroxide is: Catalytic Decomposition Catalysts speed up the rate of a reaction but are not used up in the reaction. Some catalysts provide a specific site for reaction collisions to occur. Others provide an alternative pathway for the reaction that needs a lower amount of energy to start (known as the activation energy). Hydrogen peroxide (H2O2) is a poisonous compound that gradually decomposes (breaks down) into water and oxygen gas. The rate of this reaction is very slow, however, it can be increased if some manganese dioxide (MnO2) is added. Hydrogen peroxide (H2O2) is a poisonous compound that gradually decomposes (breaks down) into water and oxygen gas. The rate of this reaction is very slow, however, it can be increased if a catalyst is used. (a) Discuss the decomposition of hydrogen peroxide using a catalyst. In your answer, you should:  Name a catalyst that would be suitable for this reaction.  Describe what would be observed during the decomposition reaction.  Explain why only a small amount of catalyst is needed to catalyse this decomposition reaction.  Write a balanced symbol equation for the reaction. answer is... Catalyst: Manganese dioxide OR potassium iodide OR animal liver OR potato OR iron(III) oxide. Description of observations: When the catalyst is added to the colourless hydrogen peroxide solution, bubbling is observed as a gas is released. The reaction releases heat. The rate of gas production is high initially but slows down over time. A catalyst is a chemical that speeds up the rate of a reaction but that is not consumed by the reaction. As one catalyst particle affects many reactant collisions only a small amount is required.

Decomposition decompose metal oxide blue blue pink speed catalysts decomposes water oxygen manganese dioxide bubbling heat catalyst collisions