Digital ACT Science Practice Question #1629

In the experiment shown in Table 1, which variable was held constant across all four trials? Passage Context (Chemical Kinetics): A chemistry research team investigated the decomposition rate of hydrogen peroxide (H2O2) into water and oxygen gas at 25°C under varying catalyst conditions. Four trials were conducted with 100 mL of 1.0 M H2O2: Table 1: - Trial 1: No catalyst | Initial rate: 0.02 mL O2/sec | Time to 50 mL O2: 2,500 sec - Trial 2: 0.10 g Fe2O3 | Initial rate: 1.15 mL O2/sec | Time to 50 mL O2: 44 sec - Trial 3: 0.10 g MnO2 | Initial rate: 8.40 mL O2/sec | Time to 50 mL O2: 6 sec - Trial 4: 0.10 g KI | Initial rate: 3.60 mL O2/sec | Time to 50 mL O2: 14 sec