March 21, 2023, 04:43:43 AM
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### Topic: Homework problems that completely stump me  (Read 15741 times)

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#### britbro19

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##### Re: Homework problems that completely stump me
« Reply #15 on: September 21, 2008, 02:58:02 PM »
For percentage we always did g of what we wanted divided by g of the sample times 100%

#### Borek

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##### Re: Homework problems that completely stump me
« Reply #16 on: September 21, 2008, 03:00:08 PM »
You want mass of chlorides - solve for that.
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#### britbro19

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##### Re: Homework problems that completely stump me
« Reply #17 on: September 21, 2008, 03:13:47 PM »
1.2 g of sample is 440.25% chlorine.

1.2 x .4025 = .483 g of chlorine in the sample

.483 g Cl x 1 mol Cl
35.452 g Cl  = .013624 mol Cl

#### Borek

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##### Re: Homework problems that completely stump me
« Reply #18 on: September 21, 2008, 03:36:46 PM »
OK, now moles af AgCl, mass of AgCl and you are ready.
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#### britbro19

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##### Re: Homework problems that completely stump me
« Reply #19 on: September 21, 2008, 03:43:47 PM »
but I thought the problem already gave the mass of AgCl?

#### Borek

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##### Re: Homework problems that completely stump me
« Reply #20 on: September 21, 2008, 03:57:01 PM »
Practical, you need a theoretical one as well to calculate percent yield.
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#### britbro19

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##### Re: Homework problems that completely stump me
« Reply #21 on: September 21, 2008, 04:00:36 PM »
So,

100-40.25 Cl=59.75% Ag

1.2 x .5975=.717 g AgCl

.717 g AgCl x 1 mol AgCl
143.32 g AgCl =.005003 mol AgCl

#### Borek

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##### Re: Homework problems that completely stump me
« Reply #22 on: September 21, 2008, 04:04:36 PM »
No. Take a look at the reaction equation. How many moles of AgCl produced for one mole of Cl? How many moles of Cl (hint: don't calculate it again, you already did it just a moment ago).
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#### britbro19

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##### Re: Homework problems that completely stump me
« Reply #23 on: September 21, 2008, 04:12:03 PM »
Ag+  + Cl- ----> AgCl

Therefore it's a 1:1 ration, so there's the same number of moles of Ag and Cl? Ok. Now what?

#### Borek

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##### Re: Homework problems that completely stump me
« Reply #24 on: September 21, 2008, 04:29:42 PM »
Now you reread the whole thread and do what I told you several times earlier. Sorry, but it is up to you to solve the question, not up to me to spoonfeed you for hours.
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#### britbro19

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##### Re: Homework problems that completely stump me
« Reply #25 on: September 21, 2008, 04:38:17 PM »
Yes, I know that. Thank-you for being so rude. But as I've told you before, we've never done this before because we've missed so much school due to hurricanes and chemistry is not the sort of subject that just clicks.

#### JGK

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##### Re: Homework problems that completely stump me
« Reply #26 on: September 22, 2008, 11:42:23 AM »
Yes, I know that. Thank-you for being so rude. But as I've told you before, we've never done this before because we've missed so much school due to hurricanes and chemistry is not the sort of subject that just clicks.

Funny that the local time in your profile puts your location as somewhere in the Mid-Pacific (at GMT-11.0). Unless I'm mistaken Hurricanes Gustav and Ike never got within 4 time zones of you.
Experience is something you don't get until just after you need it.

#### Borek

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##### Re: Homework problems that completely stump me
« Reply #27 on: September 22, 2008, 12:02:16 PM »
Funny that the local time in your profile puts your location as somewhere in the Mid-Pacific (at GMT-11.0). Unless I'm mistaken Hurricanes Gustav and Ike never got within 4 time zones of you.

That's default time zone of everyone that has not fully configured its account. IP puts britbro19 in New Orleans.

Interestingly, same IP was used over a year ago by user BRIT, asking for a... theoretical yield.

http://www.chemicalforums.com/index.php?topic=17049

What a coincidence.
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