Topscore 1 - GC #16 (#56 for total science)
Can someone explain how they got A?[/QUOTE]
Topscore GC Questions
- Thread starter MowgliR
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Topscore 1 - GC #16 (#56 for total science)
Can someone explain how they got A?[/QUOTE]
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I have troubles with new ionic equations too!
Yeah I just disassociated all the ions and crossed all of them out. I got H + OH = H2O so I just put A....and it was right.
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hopefully this helps..
Alright...bear with me on this one.
So we have
one mole of PCl5 ----> one mole of PCl3 + one mole of Cl2.
Kc = ([one mole PCl3][one mole Cl2]) / [one mole PCl5]
Our molarity of PCl5 is 14.25/3 which we can assume is between 4 and 5 but definitely closer to 5, so lets round it to about 4.7. From here we know that 40% of this 4.7M solution decomposes. So, 4.7 - 4.7(0.4) = 2.84, which is the amount we have left after the reaction has completed.
Now, looking back at the equation.
one mole of PCl5 ----> one mole of PCl3 + one mole of Cl2.
So when 40% of PCl5 decomposes, you get 0.4(4.7) = 1.88 of each amount of product formed.
Lets make one mole of product = x.
Now Kc = ([x][x])/[amount of PCl5 that we have left]
Using the values that we determined that gives us ([1.88][1.88]) / 2.84
this simplifies to (1.88)^2 / 2.84 , which most closely resembles answer choice A!!!
Ya dig?
So we have
one mole of PCl5 ----> one mole of PCl3 + one mole of Cl2.
Kc = ([one mole PCl3][one mole Cl2]) / [one mole PCl5]
Our molarity of PCl5 is 14.25/3 which we can assume is between 4 and 5 but definitely closer to 5, so lets round it to about 4.7. From here we know that 40% of this 4.7M solution decomposes. So, 4.7 - 4.7(0.4) = 2.84, which is the amount we have left after the reaction has completed.
Now, looking back at the equation.
one mole of PCl5 ----> one mole of PCl3 + one mole of Cl2.
So when 40% of PCl5 decomposes, you get 0.4(4.7) = 1.88 of each amount of product formed.
Lets make one mole of product = x.
Now Kc = ([x][x])/[amount of PCl5 that we have left]
Using the values that we determined that gives us ([1.88][1.88]) / 2.84
this simplifies to (1.88)^2 / 2.84 , which most closely resembles answer choice A!!!
Ya dig?
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hey guys, i have no clue how to post a pic like randy has...can someone fill me in? or if any of u could post # 55 on topscore from GCHEM the one w activation energy i had trouble with that one, thanks in advance!
