INS chemistry lab for weeks 6 and 7 This lab will examine the relationships between pressure, volume, temperature, and number of moles for some common gases. It was created by Dharshi Bopegedera of the TESC faculty. Experiment 1: Exploring the relationship between pressure and volume of a gas sample In this experiment we will keep the temperature and the number of moles of a gas sample constant and explore how the pressure relates to its volume. To be done in the lab: (work in pairs) 1. Locate the experimental setup for Experiment 1. You will be given directions on how to acquire data at this workstation using Vernier software and sensors. Take a few minutes to familiarize yourself with this process. Draw a block diagram of the experimental setup in your lab notebook. 2. Draw in a volume of atmospheric air (this is your “gas sample”) into the 30 mL plastic syringe. Seal off the syringe using the 3-way valve so that gas cannot move in or out of the syringe (hence the number of moles of gas is constant). This experiment is done at constant room temperature. Record the room temperature in your lab notebook. Read the volume of the gas sample in the syringe and input this information into the computer. The Vernier pressure sensor will read the pressure of the gas sample. 3. Change the volume of the gas sample by moving the plunger of the syringe. Read and input the volume of the gas into the computer. The Vernier pressure sensor will read the pressure. 4. Repeat the above process 2 more times and obtain volume/pressure data. Then let your lab partner repeat the process 4 more times and obtain volume/pressure data. Both of you should have a total of 8 data points when you leave the station. 5. Save all your data and export it into a Microsoft Excel spreadsheet. Save the Excel file. To be done individually outside lab time: 1. Plot a graph of pressure versus volume using Microsoft Excel (scatter plot). Print your graph and put in the lab notebook. 2. Plot a graph of pressure versus 1/volume using Microsoft Excel (scatter plot. Print your graph and put in the lab notebook. 3. Give your spreadsheet a suitable title. Put your data into titled columns. Add your name and date to the spreadsheet. Print out the spreadsheet and put in your lab notebook. 4. Based on the graphs you plotted, what conclusions can you draw about the relationship between the pressure and volume of a gas sample at constant temperature? Explain your reasoning. Experiment 2: Exploring the relationship between pressure and temperature of a gas sample In this experiment we will keep the volume and the number of moles of a gas sample constant and explore how its pressure relates to the temperature. Two workstations are set up for this experiment. Each workstation has two different gas samples. The gasesprovided are atmospheric air, He, CO2, and N2. You are required to work at one workstation with two of the above gases only. To be done in the lab: (work in pairs) 1. Locate one of the experimental setups for Experiment 2. You will be given directions on how to acquire data at this workstation using Vernier software and sensors. Take a few minutes to familiarize yourself with this process. Draw a block diagram of the experimental setup in your lab notebook. 2. You will be provided with two separate, sealed, 250 ml Erlenmeyer flasks (these are the sample cells). Each flask is filled with atmospheric air, He, CO2, or N2 gas. Write down the gases given to you. The Erlenmeyer flasks are connected to Vernier pressure sensors. Since the gas sample is contained in a fixed volume Erlenmeyer flask, the volume and the number of moles of gas sample remain constant throughout the experiment. 3. Prepare an ice water bath (about 0°C). Immerse the two Erlenmeyer flasks (up to the neck) in this bath and wait for the system to reach thermal equilibrium. The gas samples have reached thermal equilibrium when the pressure readings do not change with time. This will take a few minutes, so be patient. Once the system has reached thermal equilibrium, use the Vernier sensors and software to continuously record the temperature and the pressures of the two gas samples. While continuing data collection, use the magnetic stirrer/heater unit to slowly warm up the ice water bath. When the temperature reading is around 90 °C, the data collection can be discontinued. 4. Your data will be tabulated as follows with Vernier software. time (s) temperature (°C) pressure of gas ___ pressure of gas ___ 5. Save your data and export it to a Microsoft Excel spreadsheet. Save the spreadsheet and leave the workstation. 6. There is a second station set up for Experiment 2, with two gases different from the ones you used. Do not repeat the experiment at this station, but find a lab group that worked at this station and copy their data. When you are done you should have data for four different gases (atmospheric air, He, CO2, and N2). To be done individually outside lab time: 1. Give your Microsoft Excel spreadsheet a suitable title. Put your data into titled columns and add your name and date to the spreadsheet. Save your data electronically. 2. Plot a graph (scatter plot) of pressure versus temperature (in Kelvin) using Microsoft Excel for each gas sample. Print these graphs and put them in your lab notebook. 3. Based on the graphs you plotted, what conclusions can you draw about the relationship between the pressure and temperature of a gas sample at constant volume? Explain your reasoning. Compare the graphs for the four different gases and comment on your observations.Experiment 3: Exploring the relationship between volume and temperature of a gas sample In this experiment we will keep the pressure and the number of moles of a gas sample constant. To be done in the lab: (work in pairs) 1. Locate the experimental setups for Experiment 3. You will be given directions on how to acquire data at this workstation using Vernier software and sensors. Take a few minutes to familiarize yourself with this process. Draw a block diagram of the experimental setup in your lab notebook. 2. Draw in a sample of atmospheric air into the 50 mL glass syringe. Seal off the syringe with the 3-way valve so that gas cannot move in or out of it (this holds the number of moles of gas constant). During the experiment, pressure of the gas will be held constant at atmospheric pressure by allowing the plunger of