A student sets up an apparatus using a reaction flask and a gas syringe to measure the volume of oxygen gas evolved during the chemical decomposition of hydrogen peroxide () catalyzed by manganese dioxide (). Based on standard laboratory procedures, place the following steps of the experimental process in the correct chronological order from first to last.
- 1Measure a fixed volume of hydrogen peroxide solution and pour it into the reaction flask.
- 2Add a measured mass of manganese dioxide powder into the reaction flask.
- 3Insert the rubber stopper connected to the gas syringe tightly into the neck of the flask.
- 4Record the position of the gas syringe plunger at regular 30-second intervals.
Answer
The correct chronological order of the experimental procedure is: First, measure and pour the hydrogen peroxide solution into the reaction flask; second, add the manganese dioxide powder into the flask; third, tightly insert the rubber stopper connected to the gas syringe; fourth, record the volume reading on the gas syringe at regular intervals.
The correct procedure follows a logical sequence for gas generation and collection: first, the hydrogen peroxide liquid reactant is poured into the flask; second, the manganese dioxide catalyst is added to start the reaction; third, the flask is immediately closed with the stopper connected to the gas syringe to prevent gas loss; and fourth, gas syringe readings are taken over time as oxygen gas collects.
Step-by-Step Solution
Key Concept
Chronological Sequence in Experimental Apparatus Assembly and Gas Collection
Estimated Time:45s