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Topic: Math Converting g to kitchen measure, various compounds  (Read 5838 times)

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Offline harosan

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Math Converting g to kitchen measure, various compounds
« on: December 28, 2007, 08:06:11 AM »
It's been many, many moon since I took gen Chem, so not even sure this is the right forum to ask the question. What I thought was hard was relatively easy, and vice versa. I want to determine the amt of a compound to produce x ppm of a component/element in that compound (ex: g of carbonates in sodium bicarbonate) to obtain 5 ppm in water) of various compounds (all in water)  :) , then convert that to common kitchen measures (teaspoon, etc)  ???.

Once I remembered the per. table getting g was pretty easy. I remember specific gravity and density vaguely  :-[, but for the life of me can't seem to make it work. (ex: sg of sodium bicarbonate is 2.159)

I need 2.649 g of NaHCO3 to get 5 mg/l (ppm) by using a gram scale I know that 1 tsp = ~5.0 g; but, how would I determine this without using the scale.

Geese I hope I asked that correctly!

Offline enahs

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Re: Math Converting g to kitchen measure, various compounds
« Reply #1 on: December 28, 2007, 05:10:28 PM »
A tsp is a measurment of volume. You have to use density to convert the mass to volume, and vice-versa.

According to Google:
1 US teaspoon = 4.92892161 milliliters

d=m/v (density = mass/volume).

Use the density of your substance (wiki probably has it) to convert to volume, and then use the above information to convert the volume in metric units (as the density will be in metric units) to volume in tsp's.

Offline harosan

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Re: Math Converting g to kitchen measure, various compounds
« Reply #2 on: December 28, 2007, 07:11:44 PM »
Thanks so much for the assist... I was nearly on the right track... sorry if this was too trivial from the board... Obviously, I need to do a thorough review of chem before I do much more...

Again thanks

Offline Rabn

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Re: Math Converting g to kitchen measure, various compounds
« Reply #3 on: December 28, 2007, 07:57:57 PM »
There are no trivial questions when it comes to understanding the nature of things.

Offline billnotgatez

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Re: Math Converting g to kitchen measure, various compounds
« Reply #4 on: December 28, 2007, 08:15:16 PM »
Just to be a contrary and you can slap me for it.
Doesn’t it all depend on how tightly you pack the powder?
In the past they used to use sifters to make flour and other dry ingredients fluffy.


Offline Rabn

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Re: Math Converting g to kitchen measure, various compounds
« Reply #5 on: December 28, 2007, 08:18:48 PM »
you are correct billnotgatez, however packing is only relevant to compressable materials and materials with a fairly high water content, i.e. brown sugar.

Offline enahs

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Re: Math Converting g to kitchen measure, various compounds
« Reply #6 on: December 28, 2007, 08:19:27 PM »
Yes it does, billnotgatez. I was actually writing a post when you responded. This is one of the major problems with measurements in cooking. Everybody should have a good kitchen scale! Conveniently it will measure the mass in metric units and skip all these steps, and remove all the error from the packing amount!  ;D

Offline billnotgatez

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Re: Math Converting g to kitchen measure, various compounds
« Reply #7 on: December 28, 2007, 08:22:53 PM »
What do you think the weight of a pinch of salt?

Better yet the weight of salt to taste?

(I will pay for my sins)



Offline Rabn

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Re: Math Converting g to kitchen measure, various compounds
« Reply #8 on: December 28, 2007, 08:25:22 PM »
What do you think the weight of a pinch of salt?

Better yet the weight of salt to taste?

(I will pay for my sins)




The weight of a pinch of salt is relative to the size of the cooks fingers....Andre the Giant vs. Me....He wins by a lot.

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