Title: Investigating the Effect of HCl Concentration on Heat Production in the Reaction with Zinc
Objective:
To determine whether the amount of heat produced is dependent on an increase in the concentration of hydrochloric acid (HCl) when it reacts with an excess of zinc (Zn).
Materials:
1. Hydrochloric acid (HCl) with different concentrations (e.g., 1M, 2M, 3M)
2. Zinc (Zn) metal
3. Calorimeter (insulated container)
4. Thermometer
5. Graduated cylinder or burette
6. Stopwatch/timer
7. Safety goggles and gloves
Procedure:
1. Precautionary Measures:
- Put on safety goggles and gloves to protect yourself during the experiment.
- Ensure proper ventilation in the area where the experiment will be conducted to avoid the buildup of harmful fumes.
2. Setup:
- Set up the calorimeter by placing it on a stable surface.
- Fill the calorimeter with a measured amount of water (e.g., 100 mL) and record its initial temperature.
- Place the thermometer in the water and secure it without touching the calorimeter walls.
3. Reaction Setup:
- Cut a small piece of zinc metal and weigh it accurately.
- Record the mass of the zinc metal.
- Add the measured amount of hydrochloric acid (e.g., 50 mL) to the graduated cylinder or burette.
- Start the stopwatch/timer.
4. Reaction Process:
- Carefully add the hydrochloric acid to the calorimeter containing the water while simultaneously starting the timer.
- Stir the mixture gently using the thermometer to ensure uniform heat distribution.
- Observe and record the highest temperature reached by the solution.
- Repeat steps 3-4 for each concentration of hydrochloric acid, maintaining the same amount of zinc metal and water in the calorimeter.
5. Data Collection:
- Record the highest temperature attained for each concentration of hydrochloric acid.
- Calculate the change in temperature (∆T) for each reaction using the formula: ∆T = Final Temperature - Initial Temperature.
6. Analysis:
- Plot a graph with the concentration of hydrochloric acid (x-axis) versus the change in temperature (∆T) (y-axis).
- Analyze the graph to determine whether there is a relationship between the concentration of hydrochloric acid and the heat produced.
7. Conclusion:
- Based on the graph and analysis, draw a conclusion about whether the amount of heat produced depends on the increase in HCl concentration when it reacts with excess zinc.
- Discuss any limitations and possible sources of error that may have influenced the results.
Note: Before conducting the experiment, it is essential to verify that the reaction between hydrochloric acid and zinc is exothermic.