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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

Gas and Syringes

Independent Variable

Temperature

Dependent Variable

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

-15.0

4.3

4.1

Ice Water

0.9

4.6

4.6

Room Temperature Water

21.1

5.2

5.1

Warm Water

49.1

5.5

5.5

Hot Water

81.1

5.9

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.

Temperature vs Volume of a Gas 7 6

Volume (mL)

5 Volume Air (mL) Linear (Volume Air (mL)) Volume Hydrogen (mL0 Linear (Volume Hydrogen (mL0)

4 3 2 1

-20

0

0

20

40

60

80

100

Temperature °C

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! Air |-275 – (-273.15)| x 100 -273.15 -1.85/-273.15 x 100

0.677%

Hydrogen |-255 – (-273.15)| x 100 -273.15 18.15/-273.15 x 100 -6.64%

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. Air: n = PV/RT n = (1.2 atm x 0.00459 L) / (0.0821 x 273.9 K) n = 0.00024 moles air

Hydrogen

n = PV/RT n = (1.2 atm x 0.0052 L) / (0.0821 x 294.1 K) n = 22.35 moles hydrogen

Conclusion: Write a conclusion statement that addresses the following questions: My experimental absolute value and accepted value were very similar. Both numbers appeared to be very close to the line of best fit. According to my data, my hypothesis is supported due to both volume and temperature corresponding with one another. For example, when the temperature began at -15 and rose to .9, and the volume was 4.3 and then to 4.6 follows the hypothesis. The number increase and decrease mutually. Errors could potentially include: a miscalculated volume or temperature, too much time left on experiment (clock), and not enough trials. I think we can further explore this experiment by using different elements, testing different liquids other than water, and replicating the experiments alongside other scientists.

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? The line of best fit was used to determine the experimental value of absolute zero because not only does it give an estimate of the most accurate regression, but further explains itself by intersecting the x – axis on a specific point on the graph

2. Which gas law is this experiment investigating? How does your graph represent the gas law under investigation? The Charles gas law was being investigated in this experiment. According to Charles, he observes the direct relationship between volume and temperature. In our case, the graph represents the preview of correlation between volume and temperatures effects on gas. 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. The relationship between volume and temperature of an ideal gas is a statement clarifying that a specific amount of volume corresponds with temperature 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? I would use Avogadro’s law. His law is displaying pressure directly proportional with moles. The use of this law allows us to remove the first constants of the first experiment and manipulate them to be tested....