6.05 Ideal Gas Lab - Grade: a PDF

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6.05 -- Ideal Gas Lab Report Title: Measuring Volume and Temperature Gas Lab

Objective(s): Does volume and temperature correlate? If so, how?

Hypothesis: If volume and temperature increase at a constant rate, then they are considered correlated because of their ability to correspond with each other. Example: If one goes up, so does the other; vice versa Procedure: Access the virtual lab and complete the two trials of the experiment simultaneously. List your controlled variables, independent variable, and dependent variable. Explain why these are the variables. Summarize the steps of the experimental procedure. Materials: Syringe 3 Tanks of Various Gases Ice Water Salt Thermometer Watch

Variables: IV: Temperature, it is what is being changed consistently in the experiment to see the effect on other variables DV: Volume, it is what is being measured due to the changes in temperature Controlled Variables: Gas and Syringes, they remain constant the whole time and have no effect on any outcomes

Remember, controlled variables are factors that remain the same throughout the experiment. An independent (test) variable changes so that the experimenter can see the effect on other variables. The dependent (outcome) variable will change in response to the test variable.

Controlled Variables Independent Variable Dependent Variable

Gas and Syringes Temperature Volume

Summary of Steps: Examine the relationship between the volume and temperature of gas using gases sealed inside syringes. You will place the syringes in water baths at various temperatures and record their volumes. Using this data, you will calculate an experimental value of absolute zero and compare it with the calculated value.

Data: Collect your data in the table below. Don’t forget to record measurements with the correct number of significant figures. Water Bath

Temp (⁰ C)

Volume (mL) Air

Volume (mL) N2/H2/He

Ice & Salt Water Ice Water Room Temperature Water Warm Water Hot Water

-15.0 0.9 21.1

4.3 4.6 5.2

4.1 4.6 5.1

49.1 81.1

5.5 5.9

5.5 5.8

Data Analysis: Create a separate graph of temperature vs. volume for each of the gas samples. You are encouraged to use graphing software or online tools to create the graphs; be sure to take screenshots of the graphs that also include your data. Make sure to include the following on your graphs: • • • •

Title Labels for axes and appropriate scales Clearly plotted data points A straight line of best fit

The x-intercept of the volume vs. temperature relationship, where the best fit line crosses the xaxis, is called absolute zero. Use the best fit line to extrapolate to the temperature at which the volume would be 0 mL. Record this value. It is your experimental value of absolute zero. Example Graph:

This sample graph shows temperature data plotted along the x-axis and volume plotted on the y-axis. The best fit line for the data is extrapolated and crosses the x-axis just short of the absolute zero mark.

Graphing tool: https://nces.ed.gov/nceskids/createagraph/ You may find any other graphing website, or you may hand draw the graph. Google Graphing Help: https://drive.google.com/open? id=16_5c7nTBqTEGuyhSOkygZKJXZ_84K2AI Calculations: 1. The actual value for absolute zero in degrees Celsius is −273.15. Use the formula below to determine your percent error for both gas samples. Your final answer should be positive since there are absolute value signs on the numerator! |experimental value – actual value| x 100 actual value 2. If the atmospheric pressure in the laboratory is 1.2 atm, how many moles of gas were in each syringe? (Hint: Choose one volume and temperature pair from your data table to use in your ideal gas law calculation.) Use PV=nRT to solve for n. Make sure you use the right R value.

Conclusion: Write a conclusion statement that addresses the following questions:    

How did your experimental absolute zero value compare to the accepted value? Does your data support or fail to support your hypothesis (include examples)? Discuss any possible sources of error that could have impacted the results of this lab. How do you think the investigation can be explored further?

Post-Lab Reflection Questions Answer the reflection questions using what you have learned from the lesson and your experimental data. It will be helpful to refer to your chemistry journal notes. Answer questions in complete sentences. 1. Why was the line of best fit method used to determine the experimental value of absolute zero? 2. Which gas law is this experiment investigating? How does your graph represent the gas law under investigation? 3. Using your knowledge of the kinetic molecular theory of gases, describe the relationship between volume and temperature of an ideal gas. Explain how this is reflected in your lab data. 4. Pressure and number of moles remained constant during this experiment. If you wanted to test one of these variables in a future experiment, how would you use your knowledge of gas laws to set up the investigation?...