CHM3910

  

CHM3910 — Fall 2018 

please show your work for all calculations, and report answers to the proper number of significant

digits to receive full credit. For calculations, circle your final answer. Use a separate piece of paper to

answer these questions.

1. Read section 4.3 in Barrante. and review the rest of chapter 4. Then complete questions 2(a), 2(c)

and 2e) from the end of the chapter.

2. Given that the gas constant. R = 8.3144 J K" mol“, express R in Pa cm3 K" per molecule.

3. Estimate the constant pressure heat capacity (C y) of methane at 298 K using the equipartition

theorem:

a. including vibrational energy in your estimate, and

b. ignoring the vibrational contribution to the heat capacity.

c. Look up the actual constant pressure heat capacity of methane using the NlST Webbook (link

in the Resources folder on D2L - be sure to list their reference for where this value is from),

and compare it with your results from (a) and (b). Which compares better with the true

value“? Explain.

4. An athlete who is working hard typically inhales 4.0 L of air per breath, at 1.00 atm and 298.15 K.

The inhaled air contains 0.50% by volume of water, and the exhaled air contains 6.2% by volume of

water. If the athlete takes 40. breaths per minute, determine the number of moles of water expelled

via the lungs each minute.

5. A balloon containing 13.25 L of He at 15.4 °C and 1.00 atm rises to a height in the atmosphere wh

the pressure is 248 Torr and the temperature is —30.5 “C. Determine the final volume of the balloon

assuming that the pressure inside and outside the balloon is equal.