Final answer:
If the sample of NaClO3 had been heated 20 °C higher, the decomposition would have taken approximately 24 min.
Step-by-step explanation:
In the given question, we are told that the rate of a reaction doubles for every 10 °C rise in temperature.
Now, to find approximately how long the decomposition of NaClO3 would have taken if the sample had been heated 20 °C higher, we can use the information given in the question.
Since the rate doubles for every 10 °C rise in temperature, a 20 °C rise would result in the rate being quadrupled. Therefore, the time taken for the decomposition would be halved.
So, if the sample took 48 min to be 90% decomposed, it would have taken approximately 24 min if it had been heated 20 °C higher.