Part 2: Analyze the Temperature Experiment
Step 1: Graph Your Data
Here is a sample representation of the data collected from the temperature experiment, shown in a table format for easy reference before graphing.
| Water Temperature (°C) | Time to Dissolve (seconds) | |-------------------------|-----------------------------| | 85°C | 45 seconds | | 22°C | 60 seconds | | 5°C | 120 seconds |
Using this data, a graph can be plotted with the water temperature on the X-axis and the time to dissolve on the Y-axis. Generally, as the temperature increases, the time to dissolve should decrease.
Step 2: Questions
What is the independent variable?
The independent variable in this experiment is the water temperature.
What is the dependent variable?
The dependent variable is the time taken for the antacid tablet to dissolve.
Analyze the data.
The data reveals a clear pattern: as the temperature of the water increases, the time needed for the antacid tablet to dissolve decreases. This suggests that increased temperature enhances the reaction rate, which aligns with the principle that higher temperatures increase molecular motion, leading to more frequent and effective collisions between reactant particles.
Statistical Features and Limitations:
One potential source of error in this experiment could be inconsistent measurements of temperature, as well as differences in the exact size or dissolution time of the antacid tablets. If the tablets or the amount of water used in each cup was not exactly the same, this could lead to variability in the results. Additionally, the measurement timing could vary based on human reaction time. Limitations include only testing three temperature points, meaning more thorough analysis could be achieved by testing additional temperatures.
Everyday Activity Suggestion:
An everyday activity that mirrors this experiment is combining salt in hot water versus cold water. Salt dissolves more quickly in hot water, demonstrating the effect of temperature on solubility similar to the antacid experiment.
What quantitative relationships were present in your data?
The quantitative relationship observed is the inverse correlation between temperature and time taken to dissolve. Specifically, the data suggests a clear trend where higher temperatures correlate with shorter dissolution times.
What mathematical calculations were needed before you could draw conclusions?
Basic calculations to average dissolution times and potentially determine a rate of dissolution could be useful. For instance, one could calculate an average rate of dissolution per degree of temperature rise, potentially showing how much the time decreases with each increase in temperature.
Notes
- Observed that in warmer water, the fizzy reaction from the antacid tablet was more vigorous.
- Ensured that the same type of antacid tablet was used and that measurements reflected consistent conditions.
Part 3: The Concentration Experiment
Step 1: Plan and Conduct Experiment
What evidence and facts do you need to collect?
Data on how long it takes for the antacid tablet to dissolve at various concentrations of the tablets in equal volumes of water.
What are the independent and dependent variables?
- Independent variable: Concentration of the antacid tablets (number of tablets per fixed volume of water).
- Dependent variable: Time taken for the tablet to dissolve.
How will you measure the reactant concentration?
Concentration will be measured by varying the number of antacid tablets in a fixed volume of water (e.g., 100 ml in each cup).
What are the steps in your procedure?
- Label 4 cups (Cup 1, Cup 2, Cup 3, Cup 4).
- Prepare equal volumes (e.g., 100 ml) of water in each cup.
- Add different amounts of antacid tablets to each cup (e.g., Cup 1 - 1 tablet, Cup 2 - 2 tablets, Cup 3 - 3 tablets, Cup 4 - 4 tablets).
- Simultaneously start a timer as each tablet is added to the water.
- Record the time taken for each tablet to completely dissolve in each cup.
- Repeat each trial to ensure consistency and accuracy in your results.
Record Data and Notes
As I conduct the experiment, I will record the time taken for each concentration in a table similar to Part 1.
| Number of Antacid Tablets | Time to Dissolve (seconds) | |---------------------------|-----------------------------| | 1 | | | 2 | | | 3 | | | 4 | |
Step 2: Graph Your Data
Once the data is collected, it can be entered into a graph with the number of tablets (concentration) on the X-axis and the time taken to dissolve on the Y-axis.
Step 3: Analysis
Suppose you measured reactant concentration when increasing the volume of water used in each cup. A friend chose to measure reactant concentration by dropping more than one antacid tablet into equal quantities of water. Will your graph look the same as your friend’s graph? Explain your reasoning.
My graph would likely look different than my friend's graph. I would expect that as my concentration of tablets increases, the time to dissolve would decrease steadily due to more reactants being available. My friend’s method of increasing the number of tablets while keeping the volume constant could show a different relationship because the saturation could affect the reaction dynamics differently.
Extend the line of your graph. What do you think will happen to the reaction as the concentration of the reactant particles approaches zero? Why?
As the concentration of the reactant particles approaches zero, the reaction rate would slow significantly, and ideally, the dissolution would take an infinitely long time, as there would not be enough reactant particles to facilitate a significant reaction. Hence, the rate of reaction is directly dependent on the concentration of reactants.