Chemistry question :)
 

Didn't know where to put this so feel free to move it :)

Here's something to frazzle your brains

You are provided with a solution containing 50ppm chloride ions. How many mls of this should be taken and diluted to produce 100ml of a 2.5ppm solution?

Re: Chemistry question :)
 

5 ml ?

Re: Chemistry question :)
 

:rolleyes: The only mark I got in my chemistry exam was for spelling my name correctly so don't be looking to me :erm:

Re: Chemistry question :)
 

ummmm (swigs a beer)


TAKE 100 ml of the solution, dilute in half, then throw half away ??

Re: Chemistry question :)
 

20mls :rofl: wtf do I know???

Re: Chemistry question :)
 

I'd say 20 ml

Re: Chemistry question :)
 

How did you come to that conclusion?

Re: Chemistry question :)
 

You didn't tell us what volume of the original solution we had :D

Re: Chemistry question :)
 

Gut feeling is with pem, 5 mils, but something tells me it might be 5.263 or 4.762, but I haven't quite figured it out yet (ie, I may well be wrong).

To Ramrod, I think that may drop out of the equation...

Re: Chemistry question :)
 

How did you come to that conclusion?

Re: Chemistry question :)
 

Doesn't matter, taking 10ml for instance, out of 100ltrs of 50ppm solution will still contain the same number of ions as taking 10ml out fo 100000ltrs of a 50ppm solution :)

Re: Chemistry question :)
 

We are assuming that both the original solution and the dilutant have an equal number of molecules per mil aren't we?

Re: Chemistry question :)
 

:blush: :D

Re: Chemistry question :)
 

Right, I will try an explanation for the 5 mil answer then. Assuming 1 million parts per mililiter, you need add add 19 mils of solution (going by my above assumption) to get to 2.5 ppm. This makes 20, so multiply both by 5 to get to 100 total. So, 5 mils of the original

Re: Chemistry question :)
 

I concur

Re: Chemistry question :)
 

Incog gets out deckchair and drink,gets comfy and waits for Theodoric to arrive. slurp,slurp.

Re: Chemistry question :)
 

ok ppm is mg/kg

you want 100mls or 0.1kg of solution with 2.5 mg/kg concentration - i.e. 0.25mg of chloride ion.

50ppm is 50mg of chloride ion per litre so you would take 0.005 ml of the original solution? (ignoring density effects;) )

Re: Chemistry question :)
 

I'm waiting for Dr. Exacters to reply to my last post. What manners are that? Somebody gives an answer, the reply is: 'how did you arrive at that'?, and then he bloody disappears?

I want my grade. NOW!!!!! :afire: (and feedback on how to improve my answer if/when it's wrong) :)

Re: Chemistry question :)
 

It needs to be diluted by a factor of of 50/2.5 = 20. 1/20 of 100 is 5. So, take 5 ml of the 50 ppm solution and dilute to 100 ml.

Re: Chemistry question :)
 

I've just noticed this. I'm obviously getting a reputation for something or other. :)

PS It's not specifically a chemistry question, more a maths question on proportions, the sort of thing that was taught in school when I was a young lad (mutter, mumble, things were different in my young days . . .).

Re: Chemistry question :)
 

5ml is correct

Re: Chemistry question :)
 

Am I going to get a "see me" written in red :erm:

Re: Chemistry question :)
 

5ml of 50ppm solution = 5/1000 x 50 mg = 0.25mg

you are correct - my .005 was in kg/litres, not ml :dunce:

- can I have marks for my 'workings out' :D

Re: Chemistry question :)
 

Full marks to PEM then, as he got it first...

Re: Chemistry question :)
 

I'm probably getting extra homework :D

Re: Chemistry question :)
 

That'll cut down your postings.;)

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:dunce: Ramrod :dunce: Me

sat at the back of the class :wavey:

Re: Chemistry question :)
 

tries to be good at sport, so the 'nerd' sticker, falls off - and I got it wrong:)

Re: Chemistry question :)
 

It's really annoying because I actually got A level chemistry....but when you don't use it for 16 years.... :rolleyes: :shrug:
...but thanks for the moral support :ghugs:

Re: Chemistry question :)
 

See Me later, girl.............

Re: Chemistry question :)
 

Sorry - I had a load of stuff to do tonight - I just had a minute spare to answer the question so i did - I was 99% certain of the answer. :D

Re: Chemistry question :)
 

Complete git :D

Re: Chemistry question :)
 

and a show off :rofl:

and xaccers too :)

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:eek: :( :cry:

It was a maths question - I am naturally very good at maths. :PP:

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I've not shown off to you yet :naughty:

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you know I'm waiting :naughty:

Re: Chemistry question :)
 

Yes Mr Nikko :D

lol thanks for the rep and comment, me ------> :rofl:

Re: Chemistry question :)
 

Do your own homework, don't expect us to do it for you!!

:D

Re: Chemistry question :)
 

It wasn't my homework.
She's sexy and I just had to help, but I worked it out just after I posted the question (and just after I killed one of the servers at work installing SP4) :D

Re: Chemistry question :)
 

i had a Chemistry kit at age 15 :naughty: it was some what **** as you where very limited as to the stuff you could do with it

yes am high right now:smokin: :smokin: