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19 Nov 2019

pre lab question:

1. Assume for the moment that air consists of 80.00% nitrogen (N2) and 20.00% oxygen (O2) by volume. Use these figures and typical values for temperature and pressure (1.000 atm and 25.00°C) to calculate the density of air in g/L.

2. Explain how you will determine the mass of CO2 gas in your flask.

3. This experiment will require you to know the volume of the air/gas present in your flask. How will you measure this volume?

4. If you are use a graduated cylinder with markings in increments of 0.2 mL to measure liquids, you should interpolate and record volume readings to the nearest what?

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Hubert Koch
Hubert KochLv2
3 Aug 2019

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Related questions

This lab will require you to determine the number of moles of carbon dioxide in a flask. This will require you to know the volume of the flask, the temperature of the gas inside it, and the pressure of the gas. Give a one-to two sentence explanation of how each of these things will be determined.

(a) Assume for the moment that air consist of 80.00% nitrogen and 20.00% oxygen by volume. Use these figures and typical values for temperature and pressure (1.000 atm, 25.0 ºC) to calculate the density of air.

(b) This calculation affords a good approximation of the density of air at sea level. However, your lab is at an altitude approximately 777 meters (2550 feet). Knowing this, will the density of air in you lab be higher or lower than the value you just calculated? Why?

(c) Besides altitude, what else affects the atmospheric pressure? Where could you find the actual atmospheric pressure at the time of the experiment?

Molar Mass of CO2

Objective : Calculate the molar mass of CO2 (dry ice). Make sure this is handwritten in the lab notebook.

Procedure :

Note : During the lab, look for a qualitative observation that proves CO2(g) is denser than air.

(1) Weigh the empty 250mL Erlenmeyer flask with a rubber stopper on.

What is the volume of the air inside?

(2)Obtain few small pieces of CO2(s) in the flask. The total amount should be close to the given rubber stopper in size. Let it sublime. Make sure the pieces are small enough so you can see them ‘sing’ and ‘dance’.

(3) When sublimation is done, cap it with the stopper and weigh it. We are assuming that the container is completely filled with CO2 at this point.

* What does this mass contain?

(4) Measure the temperature of CO2.

* are you losing come CO2 as you insert the thermometer into the flask?

(5) Fill the flask all the way to the rim with water and put the rubber stopper on. Water will spill over. Pour the water into 50mL/100mL graduated cylinder (multiple times) and measure the total volume of water.

(6) Measure pressure of the air using the barometer on the wall. Go to the “HOW TO… “ linkn on the class website to watch the video on how to read the barometer!

Question:

What’s making the small pieces of CO2 “sing and dance”?

Please explain step by step. DO not use the previous / existing chegg answer!

Experiment 3: Charles’ Law (Part 2)

Using the air in a flask, measure the change in volume with temperature.

Materials:

2-Hole Rubber stopper
250 mL Erlenmeyer flask
Thermometer
100 mL Graduated cylinder
10 mL Syringe
Syringe dispensing tip

*Microwave or stovetop
*Ice
*Water
*Water bath container

*You must provide

Procedure

Connect the syringe dispensing tip to the end of the syringe.

Set up your experiment by unscrewing the cap off the 250 mL Erlenmeyer flask. Then, press the 2-hole rubber stopper into the 250 mL Erlenmeyer flask. Push the thermometer into one of the holes in the stopper, and the syringe dispensing tip (connected to the syringe) in the remaining hole.

Create an ice water bath by filling an empty container (large enough to fit the 250 mL Erlenmeyer in it) with water and ice. The exact volumes do not matter.

Place the flask in the bath and allow the flask to cool to 0 °C (32 °F). You may need to pour additional ice around the flask to sufficiently decrease the temperature.

Monitor the temperature until the air reading in the flask is 0 °C.

Remove the flask from the ice bath and discard the ice/water from the bath container.

Allow the flask to warm to room temperature. As the flask warms up, record the volume on the syringe and the temperature on the thermometer in Table 4. The volume and temperature at room temperature are the initial (Time = 0) data. Note: The gas in the flask expands as it warms, slowly pushing the piston out of the syringe. The total volume of the gas in the system is equal to the volume of the flask plus the volume of the syringe.

Use the graduated cylinder to measure and add 100 mL of hot (but not boiling) water to the water bath container and place the flask in the warm water.

Continue to record the volume reading on the syringe and the temperature on the thermometer as the gas in the flask heats every five minutes for 30 minutes. Record your results in Table 4.

Table 4: Temperature vs. Volume Data

Syringe Volume (mL) and Temperature (°C) at Room Temperature (Step 7)

Time (minutes)

Temperature (°C)

Total Volume (mL)

0

5

10

15

20

25

Post-Lab Questions:

Graph your results as temperature vs. total volume. Draw a best-fit straight line through your data pointsand determine the formula for the line in Y = mx +b form. Don’t forget to title your graph and label your axes. You may also use a graphing software program for more accurate data plots.

According to your graph, what would the total volume be at a temperature of 70 °C? 30 °C?

How do your results demonstrate Charles’ Law? Use mathematical expressions to explain your answer.

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