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Topic: The mass of a solid milk present in a 50 ml aliquot from 250 ml aliquot?  (Read 3695 times)

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Offline duma

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I'm in a quantitative analysis lab.

We're doing determination of Calcium in Milk

One of the questions on the lab write up is:

7. The mass of a solid milk present in a 50 ml aliquot =?

The 50 ml aliquot came from a 250 ml aliquot I made with the milk and distilled water.
I used 2.9644 g of the milk to make the solution.

I took 50 ml from the 250 ml aliquot, 3 times

So now it's asking me to give the mass of solid milk present in a 50 ml aliquot.

Is it just 2.966g/3?

That's the only thing I could come up with.

Thanks in advanced.

Offline mjc123

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Re: The mass of a solid milk present in a 50 ml aliquot from 250 ml aliquot?
« Reply #1 on: October 26, 2014, 04:20:57 PM »
The obvious answer would be 2.9644/5 (I say obvious, but it's clearly not obvious to you. Do you understand what you're doing at all?)
But the reference to solid milk is puzzling, as milk is a liquid (unless you're working in freezing temperatures because your department hasn't paid its heating bills). So does it mean milk solids, i.e. the solid residue left when all the water has been removed? The problem is you haven't given enough information. There must be at least 6 other questions, as well as an experimental procedure. Why don't you tell us more about what you did?

Offline duma

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Re: The mass of a solid milk present in a 50 ml aliquot from 250 ml aliquot?
« Reply #2 on: October 26, 2014, 04:34:17 PM »
solid milk because we used powdered milk. Not liquid milk. Wouldn't that be a bit obvious to you if I wrote "SOLID" milk several times? You think milk exists in liquid form only?

And yes I know what I'm doing. I am just confused about part.

I already wrote what is happening up until this portion of the lab.

Made a mixture of milk and distilled water in 250 ml flask.

Took 50 ml from that flash and used it to titrated with standard EDTA.

I want to know the mass of SOLID MILK in each 50 ml aliquot. Y
« Last Edit: October 26, 2014, 06:56:02 PM by Borek »

Offline duma

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Re: The mass of a solid milk present in a 50 ml aliquot from 250 ml aliquot?
« Reply #3 on: October 26, 2014, 04:35:13 PM »
Why would it be 2.9644/5?


Offline duma

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Re: The mass of a solid milk present in a 50 ml aliquot from 250 ml aliquot?
« Reply #4 on: October 26, 2014, 05:33:08 PM »
The obvious answer would be 2.9644/5 (I say obvious, but it's clearly not obvious to you. Do you understand what you're doing at all?)
But the reference to solid milk is puzzling, as milk is a liquid (unless you're working in freezing temperatures because your department hasn't paid its heating bills). So does it mean milk solids, i.e. the solid residue left when all the water has been removed? The problem is you haven't given enough information. There must be at least 6 other questions, as well as an experimental procedure. Why don't you tell us more about what you did?

I figured it out. It's not 2.9644/5

It was 2.9644 x 50ml / 250
« Last Edit: October 26, 2014, 06:56:23 PM by Borek »

Offline DrCMS

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Re: The mass of a solid milk present in a 50 ml aliquot from 250 ml aliquot?
« Reply #5 on: October 26, 2014, 05:56:14 PM »
I figured it out. It's not 2.9644/5

It was 2.9644 x 50ml / 250


You do realise that 2.9644/5 ≡ 2.9644 x 50ml / 250ml ??

Don't be a dick next time when youre helping someone buddy. Don't help someone if youre gonna be a douche bag about it.

mjc123 was not being a dick they were trying to help you by getting you to do the work it out in small steps.  We do not just give the correct answers around here we point you in the right direction and help you work it out yourself.


The next time you come here looking for help DO NOT insult the people who try to help.
« Last Edit: October 26, 2014, 06:57:16 PM by Borek »

Offline mjc123

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Re: The mass of a solid milk present in a 50 ml aliquot from 250 ml aliquot?
« Reply #6 on: October 27, 2014, 06:42:06 AM »
Mr Happy doesn't sound very happy.
I'm sorry if I misunderstood you, but in my language milk is a liquid. Powdered milk doesn't become "milk" until it's mixed with water. Anyway, it illustrates my point that you didn't give enough information about what you did.
And I don't want to insult anyone's intelligence, but when you suggest the answer is 2.966/3, presumably because you took 3 aliquots, what am I expected to think but that you don't understand the process? If so, believe me, you wouldn't be the only one on these forums.

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