; Nuclear Chemistry Properties of Alpha Beta and Gamma Radiation
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Nuclear Chemistry Properties of Alpha Beta and Gamma Radiation

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									                            CHEM105—Lab 6:
                   Greenhouse Gases and Global Warming

Work in pairs. One person should be the „Breather‟ throughout the entire lab.
[Note: retain at least 5 significant figures in every calculation until your very final answer
for this lab—the percent of CO2 in our atmosphere due to human respiration.]

Part 1: Determining how many moles of air you breathe out in one year.

Determine the volume of a normal breath by blowing, through the gas dispersion tube
provided, into an inverted graduated cylinder filled with water set in a 600 mL beaker.
Make several measurements and average them. Watching a clock, count the number of
breaths you take per minute and calculate the volume of air you exhale in a year.
Part 1 Questions to consider:
   1. How many liters of air do you exhale in one year?
   2. How many moles of air do you exhale in one year? (Assume ideal gas at 298 K and
      1.00 atm pressure)
Part 2: Determining how many moles of CO2 you breathe out in one year.

Measure the moles of CO2 in your exhaled breathe by using 500 mL of the provided NaOH
solution with 10 drops of phenolphthalein indicator and measuring the volume of breath
needed to turn the solution colorless. The equation for the reaction is

                                CO2(g) + OH¯(aq) → HCO3¯(aq)

Make several measurements and average them to obtain an average volume of breath
needed to neutralize the NaOH solution.
Part 2 Questions to consider:
   1. From your “titration” of NaOH with CO2, how many moles of CO2 were required to
      reach the endpoint?
   2. Calculate the gaseous concentration of CO2 in your breath (in moles CO2 /L breath).
   3. How many grams of CO2 do you exhale in one year?
   4. One of the environmental concerns is that increasing the concentration of CO2 is
      causing more IR radiation to be absorbed by the atmosphere, causing a warming
      trend around the Earth. Use your experimental measurements to calculate the
      grams of CO2 exhaled per year by the 6 billion humans on Earth. Assume that
      everyone breathes exactly like you!
Part 3: IR Spectroscopy

Look at the IR spectra listed under “Unknown Spectra” in the lab manual appendices. Using
Table 1, determine what gas created each IR spectrum. Draw vibrations for each
absorption. Report answers in results worksheet.
CHEM105 Lab #6                                                                         p. 1/1

								
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