A student investigates the rate of decomposition of sodium chlorate(I) solution:
2NaClO→2NaCl+O2 2\text{NaClO} \rightarrow 2\text{NaCl} + \text{O}_2 2NaClO→2NaCl+O2The student uses a conical flask connected to a gas syringe to collect the oxygen gas.
The student keeps the amount, in moles, of NaClO\text{NaClO}NaClO in the solution constant at the start of each experiment.
State two properties of the solution that he should keep the same to ensure that the initial amount of NaClO\text{NaClO}NaClO is the same in each experiment.
The student carries out the experiment five times using a different solid metal oxide each time to see how effective each solid is as a catalyst.
He records the time taken to collect 60 cm360\text{ cm}^360 cm3 of oxygen in the gas syringe.
| Solid metal oxide | Time to collect 60 cm360\text{ cm}^360 cm3 of oxygen (seconds) |
|---|---|
| Oxide A | 110 |
| Oxide B | 35 |
| Oxide C | no oxygen collected |
| Oxide D | 12 |
| Oxide E | 72 |
Which oxide does not seem to act as a catalyst?
Which oxide is the most effective catalyst?
In the first experiment, the student added 3.0 g3.0\text{ g}3.0 g of Oxide A.
Describe what he could do with the contents of the conical flask at the end of the experiment to show that Oxide A was acting as a catalyst, and not as a reactant.
The student repeats the experiment using two new oxides, M and N. This time, he records the volume of oxygen collected at 151515-second intervals.
The results are shown in the table below:
| Time (seconds) | Volume of oxygen collected for Oxide M (cm3\text{cm}^3cm3) | Volume of oxygen collected for Oxide N (cm3\text{cm}^3cm3) |
|---|---|---|
| 0 | 0 | 0 |
| 15 | 54 | 24 |
| 30 | 78 | 45 |
| 45 | 88 | 62 |
| 60 | 90 | 75 |
| 75 | 90 | 84 |
| 90 | 90 | 90 |
Calculate the average rate of oxygen production for Oxide N during the first 30 seconds30\text{ seconds}30 seconds of the reaction.
Estimate the volume of oxygen collected after 50 seconds50\text{ seconds}50 seconds for Oxide N.
Use the data to explain how it shows that the reaction is faster with Oxide M than with Oxide N.
