Standard level
A catalyst is a substance that affects the rate of a chemical reaction without being used up. Catalysts are very important in industry and biological catalysts enzymes) are essential for life.
Background
Hydrogen peroxide contains a peroxide bond, easily broken even at room temperature. Hydrogen peroxide is usually kept in darkened glass bottles to prevent decomposition by light.
Manganese(IV) oxide can provide a mechanism with lowered activation energy, accelerating the decomposition reaction.
Chemicals
- Hydrogen peroxide, 5 vol
- Manganese(IV) oxide
Apparatus
- Volumetric flask, 250ml
- Burette, 50ml
- Pipette, 25ml
- Pipette, 10ml
- Conical flask, 100ml
- Rubber bung
- Gas syringe
- White tile
- Clamp, boss and stand
- Small plastic container
- Timer
The reaction rate
- Weigh out about 0.5 g of manganese(IV) oxide into the plastic container.
- Pipette 25ml of the hydrogen peroxide (0.4 mol dm-3) solution into the 100 ml conical flask
- Using some long tweezers, carefully place the plastic container with the manganese(IV) oxide into the conical flask and insert the rubber bung.
- Connect the gas syringe to the side-arm.
- Simultaneously, shake the tube to mix the reactants and start the timer.
- Record the volume of oxygen produced every 10 seconds.
- Repeat the procedure for reliability.
- Hydrogen peroxide is an oxidising agent
- Manganese(IV) oxide is toxic