mangos3
04-20-2006, 04:47 PM
Can anyone explain to me how you figure that H2 is the gas that evolves? Similar problem for #41 in AAMC 5R. How do you figure out the identity of the gas? Any general rules?
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View Full Version : Aamc 8 #47 mangos3 04-20-2006, 04:47 PM Can anyone explain to me how you figure that H2 is the gas that evolves? Similar problem for #41 in AAMC 5R. How do you figure out the identity of the gas? Any general rules? xanthomondo 04-20-2006, 05:36 PM Can anyone explain to me how you figure that H2 is the gas that evolves? Similar problem for #41 in AAMC 5R. How do you figure out the identity of the gas? Any general rules? The best way to go at this problem is just eliminate bad answers... The only things present are Ca and H2O.... Since Calcium exists as a cation in solution, it makes sense that Ca(OH)2 or CaO would form.... If you balanced this equation, you would have excess H left over, which you can just write off as gas... If you think about it the other way, if O2 formed, you would have all sorts of H+ forming...this obviously can't intereact with the Ca2+, theyre both positive, and it couldn't form hydronium because there would be some charge balancing issues (what negative charge present would cancel out the positive of the calcium AND H3O+?) mangos3 04-21-2006, 06:06 AM Isn't there a compound CaH2 as well? Why couldn't that be formed? How would you reason #57 (also in AAMC 8)? |