How can I tell from a graph of temperature vs. time if a reaction is endothermic or exothermic?

My final temperature was higher than my initial temperature, and my graph shows that the temperature icreases and then decreases. I thought that would make it exothermic, but don't exothermic reactions give off heat? If someone could clear this up, I would really appreciate it! Thank you.

I think you're right. Exothermic means heat is given off; therefore, T must rise.

To determine whether a reaction is endothermic or exothermic from a graph of temperature versus time, you need to look for specific patterns in the data.

Here's how you can analyze the graph to make this determination:

1. Identify the initial temperature: Look for the starting point on the graph, which represents the initial temperature before any reaction occurs.

2. Examine the changes in temperature: Observe how the temperature changes as time progresses. In an exothermic reaction, the temperature tends to increase since the reaction releases heat into the surroundings. In contrast, an endothermic reaction absorbs heat from its surroundings, causing the temperature to decrease.

3. Focus on the slope: Determine the slope of the temperature-time graph. If the slope is positive, it indicates that the temperature is increasing, suggesting an exothermic reaction. On the other hand, if the slope is negative, it suggests a decrease in temperature and an endothermic reaction.

4. Look for plateaus: In some cases, the graph may show a plateau or a horizontal line. If you observe a horizontal line at a specific temperature, it could indicate an energy-absorbing process, implying an endothermic reaction. Conversely, if there is a plateau at a certain temperature, it may represent an energy-releasing process, suggesting an exothermic reaction.

Remember that these observations are general guidelines and may depend on the specific experimental conditions and nature of the reaction. Therefore, it is crucial to interpret the graph in the context of the experimental setup, including any known reactants and products involved.