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Topic: Calculating the molarity when mixing two different solutions  (Read 9739 times)

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Offline Aman24

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Calculating the molarity when mixing two different solutions
« on: April 07, 2016, 12:40:06 AM »
The problem:
You mix 45-mL of 0.1174M K2SO4 and 35-mL of 0.2504M HNO3


So i'm supposed to find the number of moles of the K2SO4 and add it to the number of moles of 0.2504, then add the two volumes, and divide the total number of moles by the total volume.

My question is, if i write a balanced equation, i get K2SO4 + 2HNO3 = 2KNO3 + H2SO4, does that mean for the number of moles of HNO3, before i add it to the number of moles of K2SO4 i have to multiply the number of moles of HNO3 by 2, because of the coefficient.

I could also be doing this problem entirely wrong by assuming a reaction is occurring and even needing to balance. There is nothing in my book talking about reactions when mixing two different solutions.

Offline Aman24

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Re: Calculating the molarity when mixing two different solutions
« Reply #1 on: April 07, 2016, 02:24:09 AM »
So i actually ended up thinking its possible to find a single molarity of two different, mixed solutions. I misinterpreted what my professor said. So its only possible to find concentration of ions present if given two different solutions.

Offline AWK

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Re: Calculating the molarity when mixing two different solutions
« Reply #2 on: April 07, 2016, 02:53:02 AM »
This is a simple problem of dilution. No reaction proceeds. In the final solution you may calculate concetration of compounds or ions.
AWK

Offline Aman24

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Re: Calculating the molarity when mixing two different solutions
« Reply #3 on: April 07, 2016, 03:00:31 AM »
This is a simple problem of dilution. No reaction proceeds. In the final solution you may calculate concetration of compounds or ions.

i think im finally understanding this, so molarity is just the total moles per volume, unspecific to the solution. So i would find the molarity for two different solutions the same as two same solutions.

but, i think if there was a reaction, then it would be very different.

Offline AWK

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Re: Calculating the molarity when mixing two different solutions
« Reply #4 on: April 07, 2016, 03:48:10 AM »
You should find molarities of two substances in the mixed solution or molarites of ions (taking into account a complete dissociation of both substances).
AWK

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