2. AIRWATERSOLIDS MASS/MASS ppm, ppbppm, ppb, mg/kg, μg/g MASS/VOLUME pg/L, ng/m 3 mg/L, μg/L MOLE/VOLUME nmol/m 3 mmol/L VOLUME/VOL. ppm v MOLE FRACTION dimen- sionless PARTIAL PRESSURE Atm, mm Hg, psi, Pa, Bar

3. IDEAL GAS LAW R = 0.08205 L-atm/mole-K

4. PREFIXSYMBOLMAGNITUDEExample GigaG10 +9 Gg MegaM10 +6 Mg kilok10 +3 kg, km millim10 -3 mg, mm, mL microμ10 -6 μg, μm, μL nanon10 -9 ng, nm, nL picop10 -12 pg, pL See inside front cover of textbook

5. Silver gull egg © Australian Museum Biomagnification results in increased concentrations of contaminants in organisms high on the food chain as compared to lower in the food web. The concentration of PCBs in gull eggs around Lake Superior has decreased from ~70 mg/kg wet weight in the early 1970s to about 10 mg/kg in the mid 1990s. What is 10 mg/kg in units of μg/g? in units of nmol/g? Solution:

6. http://community.webshots.com/photo/ 70676468/70678448eGdnDg Lead (Pb) is a neurotoxin that impairs the normal neurological development of children. The primary mechanism whereby children obtain Pb in their bodies is ingesting soil (pica). The safety threshold for blood lead concentrations is 9 μg/dL. SOLUTION Fortunately, the average concentration in children’s blood in the U.S. has declined from >13 to < 2 μg/dL. Express 9 μg/dl in units of mol/L. The m.w. of Pb is 207.

7. Concentrations of CO 2 in the atmosphere have increased from 315 ppm v in 1960 to the current concentration of 375 ppm v. What is the current concentration in units of atm? in units of mg/m 3 ?

8. SOLUTION: First, the molecular wt. of CO 2 is 12 + 2x16 = 44 g/mole The ideal gas law states: PV = nRT Therefore the volume of 1 L of gas at 25 o C is: Assuming a total pressure of 1 atmosphere: