1.2.4 - Laboratory Activity : The Effect of a Catalyst on the Rate of Reaction

Laboratory Activity 1.2.4: The Effect of a Catalyst on the Rate of Reaction

Aim: To understand the effect of a catalyst on the rate of reaction.
Problem statement: How does the presence of a catalyst influence the rate of reaction?
Hypothesis: If positive catalyst used in the reaction, the rate of reaction will occur faster.
Variable:

	»	Fixed variable : Temperature and volume of reactants
	»	Manipulated variable : Presence of catalyst
	»	Responding variable : Rate of reaction

Material: » Hydrogen peroxide 20-volume » Manganese (IV) oxide powder

Apparatus: » Burette » Conical flask » Measurement cylinder » Stopwatch » Retort stand with clamp » Basin » Delivery tube

Procedure:

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1. 5cm3 of hydrogen peroxide is measured by measuring cylinder and pour into test tube A and test tube B. The test tubes are then placed on a test tube rack. 2. ½ spatula of manganese (IV) oxide powder is put in test tube B. 3. A glowing splinter is inserted into the mouth of both test tube A and B. 4. Observe the glowing splinter.

Observation:

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1. The glowing splinter will be ignited in test tube B. 2. The glowing splinter will not be ignited in test tube A. 3. This video shows the observation on the effect of catalyst on the rate of reaction.

Discussion:

	►	Hydrogen peroxide decomposes slowly at room temperature. ○ H2O2(aq) → 2H2O(l) + O2(g)
	►	The presence of manganese (IV) oxide which acts as a positive catalyst increases the rate of oxygen gas, which increases the rate of reaction.
	►	Manganese dioxide is a catalyst. It is not used up in the reaction. Its mass is unchanged at the end of the reaction.

Conclusion:

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The presence of a positive catalyst can increase the rate of a reaction.

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