Problems #1: Fundamentals of Aquatic ChemistryPython

Java Python Problems #1: Fundamentals of Aquatic Chemistry

The following problems cover topic seen in Lecture 3 and you could also read Chapter 3 and 4 of Environmental Chemistry, by Stanley E. Manahan, 9th ed. as reference (10 points in total, 2.5 points each). Please remember that showing the calculation process as well as paying attention to significant figures and units is important.

1.   Assuming levels of atmospheric CO2 are 390 ppm CO2, what is the pH of rainwater due to the presence of carbon dioxide? (2 points) Some estimates are for atmospheric carbon dioxide levels to double in the future. What would be the pH   of rainwater if this happens? (0.5 points)

2.   There is two liters of 0.50 mol·L- 1 NH3·H2O and 2 liter of 0.50 mol·L- 1 HCl in a laboratory. A technician wants to use them to prepare a buffer of pH=9.00 without the addition of water. How many liters of buffer can the technician pdai 写Problems #1: Fundamentals of Aquatic ChemistryPython repare at most? What are the concentrations of NH3·H2O and NH4+ in the buffer? (pKb NH3·H2O =4.74.)

3.   In a water sample with pH=6.0, [SO42-] =1.0*10-3 mol·L- 1 and you can smell H2 S. Assuming that PH2S=1.0*10-6 atm, please calculate the Eh and pE for this system (25 oC). The equation is: SO42- + 10H + + 8e → H2 S + 4H2O and lgK=42.

4.   A graduate student made some mistakes in water sampling because he lacks experience. After the onsite measurement showed that temperature is 25 ℃ and pH=7.8, the water sample bottle was put on a cart and brought back to the lab exposed to sunshine. The pH went up to 10.2 and in the headspace of the bottle, PO2 was found to be 0.4 atm. The temperature is still 25 ℃. What caused the increase in pH and Po2? What’s the difference between the pE measured in lab and onsite? (We know that for equation 1/4O2+H++e → 1/2H2O, pE0 =20