Question

2 what is the independent (manipulated) variable in this experiment? 3 if heat was added at a constant rate to the solid substance, why did the temperature remain at 18°c for approximately 8 minutes? 4 according to your graph, what would the temperature of the substance be at 23 minutes?

Explanation:

Step1: Identify the nature of the experiment

In an experiment, the independent variable is the one that is deliberately changed or manipulated by the experimenter. Here, heat is added at a constant rate to the solid substance. The heat - addition is what the experimenter controls.

Step2: Determine the independent variable

The variable that is being manipulated is the heat added to the solid substance.

Step3: Answer question 3

The temperature remains constant at 18°C for approximately 8 minutes because the heat energy is being used for the phase - change (melting) of the solid substance. During a phase - change, the heat energy is used to break the intermolecular forces rather than increasing the temperature.

Step4: Answer question 4

To answer what the temperature of the substance would be at 23 minutes, we would need the graph to analyze the trend of temperature change over time after the phase - change is complete and the substance starts to increase in temperature again. Since the graph is not provided, we cannot give a numerical answer. But the general approach would be to find the 23 - minute mark on the time - axis of the graph and then read the corresponding temperature value on the temperature - axis.

Answer:

1. The independent (manipulated) variable is the heat added to the solid substance.
2. The temperature remained constant at 18°C for approximately 8 minutes because the heat was being used for the phase - change (melting) of the solid, and not for increasing the temperature.
3. Cannot be determined without the graph.