Question

During a flashpoint analysis, apply heat to the sample so that the temperature increases at a rate of

A) 2 degrees Celsius per minute
B) 5 degrees Celsius per minute
C) 10 degrees Celsius per minute
D) 15 degrees Celsius per minute

Answer 1

The reaction is 4 times faster at 45°C and 128 times faster at 95°C than at 25°C due to the rule that the reaction rate doubles with every 10°C rise in temperature. Decomposition of NaClO3 would take roughly 12 minutes if the temperature were increased by 20°C.

Step-by-step explanation:

The student's question relates to how the rate of a reaction changes with temperature, specifically when the reaction rate doubles for every 10°C increase in temperature. Using this rule, we can answer the following:

• (a) At 45°C the reaction is twice as fast as at 25°C, and at 35°C it is also twice as fast as at 25°C. Since the reaction doubles in rate with each 10°C rise, it would be 2 * 2 = 4 times faster at 45°C than at 25°C.
• (b) At 95°C, which is 70°C higher than 25°C, the reaction rate would double seven times (one doubling for each 10°C). Hence, the reaction would be 2^7 = 128 times faster at 95°C than at 25°C.
• For the decomposition of NaClO3, if the sample had been heated 20°C higher, the reaction rate would have doubled twice (once for each 10°C increase). Therefore, the time for decomposition would be roughly one-quarter of the original time, indicating that it would take approximately 48 min / 4 = 12 min for 90% decomposition at the higher temperature.