BPinthemorning Posted August 29, 2007 Share Posted August 29, 2007 In chemestry, we had a lab where we had to mix two 10ml solutions of Barium Nitrate and Potasium Sulfate togather. Both solutions started out white, and became a milkier color. I need to know would this be defined as a chemical or physical change. I think it is physical because both were symply homogenius mixtures, and they should have mixed togather to form one homogenius mixture. Is this correct, or would they chemicaly interact with eachother? If you have any comments or previos experiance with this please post!!! (this counts as a test grade and tests are 60% of my class) Link to comment Share on other sites More sharing options...
aquaman Posted August 30, 2007 Share Posted August 30, 2007 Ba(NO3)2 + K2SO4 ---> 2KNO3 + BaSO4 I believe that is what is happening and the products are potassium nitrate and barium sulfate. I also believe that is a chemical change and the substance that gives it the milky color is the BaSO4. Now if it is a homogenous mixture or a heterogenous.... I don't know. I would guess hetero as you can probably filter the barium sulfate out. Link to comment Share on other sites More sharing options...
BPinthemorning Posted August 30, 2007 Author Share Posted August 30, 2007 I am certian it is homogenous (it has a uniform apearance throught), and I believe you are correct that it is a chemical change and you are correct in what it produces. Link to comment Share on other sites More sharing options...
asilentbob Posted August 30, 2007 Share Posted August 30, 2007 The substances change, so it is a chemical change. The 2 solutions were homegenous as the chems were dissolved in the water. You can argue about if the formed milky precipitate counts as hetero or homogeneous though. Its bloody hard to filter BaSO4... and it will settle out... but it will take a good while. And the KNO3 formed goes into solution. Personally id say something like the precipitate is evenly distributed throughout (a homogeneous mixture) since it is so fine... however it will start to become a heterogeneous mixture as the barium sulfate settles out. BTW BaSO4 is REALLY insoluble. .000034g/L or something. Link to comment Share on other sites More sharing options...
tentacles Posted August 30, 2007 Share Posted August 30, 2007 In other news, that would be a terrible waste of perfectly good barium nitrate! Link to comment Share on other sites More sharing options...
BPinthemorning Posted August 30, 2007 Author Share Posted August 30, 2007 It wasn't my idea. I had to do if for a test grade. Link to comment Share on other sites More sharing options...
aquaman Posted August 31, 2007 Share Posted August 31, 2007 In other news, that would be a terrible waste of perfectly good barium nitrate! That is what I think every time I do labs in my school. When I do them I like drool knowing that I can't do anything pyro with it. If only I could keep a little... Link to comment Share on other sites More sharing options...
asilentbob Posted August 31, 2007 Share Posted August 31, 2007 Well... with the current state of school chemistry labs those solutions were likely like .01 M... so your not using much... Link to comment Share on other sites More sharing options...
BPinthemorning Posted August 31, 2007 Author Share Posted August 31, 2007 I go to private school. We arn't as conservative. Just makes it more painfull to watch. Link to comment Share on other sites More sharing options...
aquaman Posted August 31, 2007 Share Posted August 31, 2007 Well... with the current state of school chemistry labs those solutions were likely like .01 M... so your not using much... Yeah I know it's just the point though... I just took my AP chem ch1 and ch2 test today and I'm not feeling to good about it... I hate sig figs!!!!!!!! Link to comment Share on other sites More sharing options...
BPinthemorning Posted September 1, 2007 Author Share Posted September 1, 2007 me two. Link to comment Share on other sites More sharing options...
Boomer Posted September 3, 2007 Share Posted September 3, 2007 I vote hetero, since it's a liquid and a solid now, even if the latter is evenly distributed. Link to comment Share on other sites More sharing options...
RUUUUUN Posted September 6, 2007 Share Posted September 6, 2007 It should be heterogeneous because a precipitate formed, which will settle to the bottom of the mixture. Link to comment Share on other sites More sharing options...
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