UoPX Molar Volume of a Gas Report Lab Report

Reports consist of the following sections:-Report Sheets – the completed Data and Report Sheets cut out of your lab manual.Calculations – If there are calculations, you must clearly and logically show all of the calculations to getfull credit.Discussion – Explain your results, referring to the chemistry theory where appropriate. Did the dataconform to what was expected? What does it show in relation to the experiment? If the results are notwhat was expected explain why. Possible sources of error (estimate experimental error in numericalresults). Conclusion – briefly state any final result(s), or conclusions that can be drawn from the experiment.References – any sources consulted for the writing of the report. These should be referenced (cited) inthe body of the text. Computer
The Molar Volume of a Gas
5
In this experiment, you will determine the molar volume of a gas by conducting a chemical
reaction that produces a gas, as shown in the reaction equation below.
Mg(s) + 2HCl(aq) → MgCl2(aq) + H2(g)
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You will react a known mass of solid magnesium with an excess of hydrochloric acid, in a sealed
vessel, and use the pressure change to calculate molar volume at STP.
OBJECTIVES
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In this experiment, you will
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• Measure the gas production of a chemical reaction by a pressure change.
• Determine the molar volume of the gas produced in the reaction.
• Calculate the molar volume of a gas at STP.
Figure 1
MATERIALS
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Vernier computer interface
computer
Vernier Gas Pressure Sensor
Temperature Probe
600 mL or one liter beaker
10 mL graduated cylinder
125 mL Erlenmeyer flask
Advanced Chemistry with Vernier
1.0 M hydrochloric acid, HCl, solution
small beaker for HCl solution
magnesium ribbon
20 mL gas syringe
plastic tubing with two Luer-lock connectors
rubber stopper assembly with two-way valve
balance, ±0.001 g precision
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Computer 5
PRE-LAB EXERCISE
Obtain the 125 mL Erlenmeyer flask that you will use for the experiment. Determine and record
the available volume of the flask that the hydrogen gas will occupy as it is produced from the
reaction of the solid magnesium and the hydrochloric acid solution. Account for the following
items when you determine the volume of your flask:
• A 125 mL flask does not have a volume of precisely 125 mL.
• During the experiment, you will seal the flask with a rubber stopper and the stopper will
occupy some of the volume of the flask.
• You will add 5 mL of solution (1.0 M HCl solution) to the flask.
PROCEDURE
1. Obtain and wear goggles.
2. Obtain a ~0.010 g piece of magnesium ribbon. Measure and record its mass to the nearest
0.001 g. Place the piece of magnesium ribbon in a clean and dry 125 mL Erlenmeyer flask.
3. Prepare a room temperature water bath in a large beaker. The bath should be deep enough to
completely cover the gas level in the Erlenmeyer flask.
4. Connect a Gas Pressure Sensor to Channel 1 of the Vernier computer interface. Connect a
Temperature Probe into Channel 2 of the interface. Connect the interface to the computer
with the proper cable.
5. Use the clear tubing to connect the white rubber stopper to the Gas Pressure Sensor. (About
one-half turn of the fittings will secure the tubing tightly.) Twist the white stopper snugly
into the neck of the Erlenmeyer flask to avoid losing any of the hydrogen gas that will be
produced in the reaction (see Figure 1). Important: Close the valve on the white stopper by
turning the white handle so it is perpendicular with the valve stem.
6. Obtain a small amount of 1.0 M hydrochloric acid. CAUTION: Handle the hydrochloric
acid with care. It can cause painful burns if it comes in contact with the skin. Draw 5 mL of
HCl solution into the 20 mL syringe. Thread the syringe onto the two-way valve on the white
stopper (see Figure 1). Submerge the Erlenmeyer flask into the water bath. Position the
Temperature Probe in the water bath so that the tip of the probe is not touching the beaker.
7. Start Logger Pro 3 on your computer. Open the file “05 Molar Volume” from the Advanced
Chemistry with Vernier folder.
8. With the flask still submerged in the water bath, click
to begin data collection. After
about 20 seconds, open the two-way valve directly below the syringe, press the plunger to
add all of the 5 mL of HCl solution to the flask and pull the plunger back to its original
position. Close the two-way valve.
9. Keep the flask immersed in the water bath as the reaction proceeds. Data collection will stop
after 5 minutes. You may click
to end data collection before 5 minutes have elapsed.
10. Carefully remove the white stopper from the flask to relieve the pressure in the flask.
Important: Do not open the two-way valve to release the pressure in the flask.
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Advanced Chemistry with Vernier
The Molar Volume of a Gas
11. Examine the pressure data to determine the change in pressure, ∆P, during the reaction. In
addition, determine the mean temperature of the water bath during the reaction. Record these
values in your data table.
12. From the Experiment menu, choose Store Latest Run to save your data.
13. Rinse, clean, and dry the flask for a second trial. Obtain a new piece of magnesium ribbon
and place it in the flask. Repeat the necessary steps to conduct the second trial.
14. Follow the same procedure to conduct a third trial.
DATA TABLE
Trial 1
Trial 2
Trial 3
Mass of Mg (g)
Volume of flask (mL)
Maximum pressure (kPa)
Initial pressure (kPa)
Pressure change, ∆P (kPa)
Temperature (K)
DATA ANALYSIS
1. Calculate the moles of each piece of magnesium ribbon that you used.
2. Calculate the molar amount of hydrogen gas that was produced in your reactions.
3. Calculate the volume of one mole of hydrogen gas (molar volume) at STP.
4. Compare your calculated molar volume, at STP, with the accepted molar volume of an ideal
gas at STP, 22.4 L/mol. If the values do not compare well, suggest possible sources of
experimental error.
Advanced Chemistry with Vernier
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