Engineers in south africa are hired to determine whether a river that passes through a pyrochroite (mn(oh)2) deposit meets the standards for drinking water (drinking water standard for mn = 50 ppb). the river is in contact with solid mn(oh)2 (pksp = 14.3) and has a ph of 8.0. determine the concentration of mn2+ in the river in mg/l. also, determine the ph at which the concentration of mn2+ would meet the drinking water standard. (answers: [mn2+] = 275.2 mg/l; ph=9.87).

Asample of rose gold is: 12.0 g gold, 5.0g silver, and 7.0 g copper. what is the percent copper in the sample?

Part b: study of equilibrium on solubility: mg(oh)2(s) ⇌ mg2+(aq) + 2 oh–(aq) cloudy clear (pink) 7. a. b. 8. a. b. 9. 10. 11. 12. when adding concentrated hydrochloric acid, how did the appearance of the equilibrium mixture change? the change in appearance indicated a shift in the point of equilibrium. in which direction did the equilibrium shift? (l) left (r) right explain your answer to question 7a. you should indicate which ion was added to or removed from the equilibrium mixture. when adding edta, how did the appearance of the equilibrium mixture change? the change in appearance indicated a shift in the point of equilibrium. in which direction did the equilibrium shift? (l) left (r) right explain your answer to question 8a. you should indicate which ion was added to or removed from the equilibrium mixture. upon heating in which direction is the equilibrium shifting? upon cooling in which direction is the equilibrium shifting? is the forward reaction a. endothermic explain your answers to questions 9, 10, and 11. (l) left (r) right (l) left (r) right b. exothermic

Miner's coal distributors does not mine coal itself, nor does it even store or handle the coal. instead, miner's solicits orders for low sulfur coal from other firms, then purchases the required amount from suppliers and directs them to ship the coal to its customers. what is miner's