 | Sample Lab Questions Investigation #13:
"Alka-Seltzer® and a Little Gas"
|
These questions have been taken from lab quizzes given in previous years.
Some of the answers are listed at the end.
Note: The subscripts and superscripts may not appear as such. It depends upon your web browser.
- 1.
- (1pt) Define the standard state for gases.
- 2.
- (3pts) State the ideal gas law equation. Identify each term in the equation.
- 3.
- (1pt) If the barometric pressure is Pb on the day of the Alka-Seltzer® experiment and the vapor pressure of water at the temperature of the experiment is Pwater, give the equation for the calculation of the partial pressure of the carbon dioxide (Pc) that was collected over water.
- 4.
- (1pt) An apparatus (consisting of a buret, leveling bulb, and hoses) was used to collect gas for INV #12 "Alka-Seltzer® and a Little Gas". Before each buret reading was performed, the leveling bulb was raised or lowered until the water levels in the buret and the leveling bulb were the same. Why?
- 5.
- A sample of gaseous CO2 was collected over H2O at 22oC and 748 torr. The volume under these conditions was measured to be 46.23 mL. (R = 0.0821 L•atm/mol•K, vapor pressure of H2O at 22oC = 19.8 torr)
- a. (1pt) What is the partial pressure of the CO2?
- b. (2pts) How many moles of CO2 are in the sample?
- c. (2pts) If 0.3484 g of Alka-Seltzer® produced this CO2, what was the percent HCO3- content of the Alka-Seltzer®?
Answers
| 5. | a. | 728 torr |
| b. | n = 1.83 x 10-3 mol CO2 |
| c. | 32.1% (there is 0.112 g HCO3-) |
To report any corrections, please e-mail Dr. Wendy Keeney-Kennicutt.