Students performed an experiment to study the effects of different metal oxide catalysts on the rate of decomposition of hydrogen peroxide () into water () and oxygen gas (). In each of 4 trials, the students added of a solution to a test tube at containing either a specific catalyst or no catalyst. They measured the total volume of gas produced in milliliters () over a period of 5 minutes. The experimental setups are summarized in the table below:
| Trial | Catalyst Added | Volume of Produced () |
|---|---|---|
| 1 | None | 0.2 |
| 2 | of manganese dioxide () | 14.5 |
| 3 | of copper(II) oxide () | 3.8 |
| 4 | of iron(III) oxide () | 8.2 |
To determine the baseline rate of hydrogen peroxide decomposition in the absence of any catalyst, the students should refer to the results of which trial?
- Trial 1Answer
- BTrial 2
- CTrial 3
- DTrial 4
Answer
Trial 1
The correct answer is Trial 1. A control group or baseline condition is a setup in which the independent variable being tested (in this case, the type of catalyst) is not applied or is kept at a default state. Since Trial 1 contains no catalyst, it allows the students to measure the rate of hydrogen peroxide decomposition under the default conditions, providing a baseline to compare against the trials with catalysts.
Step-by-Step Solution
Key Concept
A control group or baseline condition in an experiment is a setup that is identical to the experimental groups except that it does not receive the active treatment (the independent variable). It provides a baseline of comparison to determine whether the independent variable has an effect and to measure the magnitude of that effect.
Estimated Time:45s