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### Topic: Principles of Instrumental Analysis  (Read 1567 times)

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#### gumusonur

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##### Principles of Instrumental Analysis
« on: January 09, 2023, 08:36:30 AM »
hello dear friends,

Can anyone help with the following questions from Principles of Instrumental Analysis book? I need to find the solution but I couldn't find it on the internet. I can't look at the places I found because it is paid.

1) The following volumes of a solution containing 1.10 ppm Zn2+ were pipetted into separatory funnels each containing 5.00 mL of an unknown zinc solution: 0.00, 1.00, 4.00, 8.00 and 12.00. Each was extracted with three 5 mL aliquots of CCl4 containing an excess of 8-hydroxyquinoline. The extracts were then diluted to 25.0 mL and their fluorescence measured with a fluorometer. The results were as follows: Volume Std. Zn2+ / mL Fluorometer Reading 0.00 6.12 1.00 7.41 4.00 11.16 8.00 15.68 12.00 20.64

a) Construct a standard curve b) Calculate a linear least squares equation for the data c) Calculate the concentration of the zinc in the unknown sample d) Calculate the standard deviation of the initial ordinate of the slope and the standard deviation associated with the regression.

2) Quinine in a 1.664-g antimalarial tablet was dissolved in sufficient 0.10 M to give 500 mL of solution. A 15.00-mL aliquot was then diluted to 100.0 mL with the acid. The fluorescence intensity for the diluted sample at 347.5 nm provided a reading of 327 on an arbitrary scale. A standard 100 ppm quinine solution registered 180 when measured under conditions identical to those for the diluted sample. Calculate the mass of quinine in milligrams in the tablet.

#### Corribus

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##### Re: Principles of Instrumental Analysis
« Reply #1 on: January 09, 2023, 09:52:31 AM »
You need to show work to receive help. It's a forum policy.
What men are poets who can speak of Jupiter if he were like a man, but if he is an immense spinning sphere of methane and ammonia must be silent?  - Richard P. Feynman

#### gumusonur

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##### Re: Principles of Instrumental Analysis
« Reply #2 on: January 11, 2023, 01:13:40 AM »
I am a chemist. How can I write my work, what kind of information? This is the first time I get such a response.

#### Borek

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##### Re: Principles of Instrumental Analysis
« Reply #3 on: January 11, 2023, 04:19:38 AM »
These are trivial textbook problems that every chemist should be able to solve.

Have you sketched the calibration curve? You can attach it as an image to your post. Everything else can be just written.
ChemBuddy chemical calculators - stoichiometry, pH, concentration, buffer preparation, titrations.info

#### gumusonur

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##### Re: Principles of Instrumental Analysis
« Reply #4 on: January 13, 2023, 06:20:57 AM »
I finished school 10 years ago and now I can't. You don't have to answer every question with such arrogance. What's the point of this forum if we're going to get these answers? you do not have to answer.

#### Borek

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##### Re: Principles of Instrumental Analysis
« Reply #5 on: January 13, 2023, 08:23:26 AM »
You are missing the point: we have plenty of students wanting us to do their work. We won't. We have no choice but to treat everyone the same way and to help everyone the same way. You either show your efforts, or you are not helped, that's part of the forum rules that you agreed to when registering.

And as I wrote - you can easily attach the calibration curve as an image, and you can easily describe what you did so far to solve the problems.
ChemBuddy chemical calculators - stoichiometry, pH, concentration, buffer preparation, titrations.info

#### Corribus

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##### Re: Principles of Instrumental Analysis
« Reply #6 on: January 13, 2023, 08:57:00 AM »
Also, showing us what you've tried helps us give you a better answer to address where your lack of understanding is.
What men are poets who can speak of Jupiter if he were like a man, but if he is an immense spinning sphere of methane and ammonia must be silent?  - Richard P. Feynman