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1answer
217 views

What is wrong with storing deionized water in glass containers?

I have heard that in general storing deionized water in glass bottles is ill advised and that it is better to use plastic. Additionally this is especially important for water used in ICP. I have ...
1
vote
1answer
451 views

Determination of hardness of water using EDTA

Finding hardness of water by using EDTA. For determining permanent hardness we take the sample of about $\pu{50 mL}$ and then add Eriochrome Black T (EBT) indicator that results in wine red color due ...
-1
votes
1answer
456 views

Hardness of water using EDTA calculation issue

I have been asked to work out the hardness of water in German degrees and this is what I did: I got a sample of water I didn’t measure how much I put into my volumetric flask perhaps it was $\pu{8....
4
votes
0answers
66 views

Should I add more of a trihydrate chemical to a solution if recipe calls for hemihydrate?

I am running phosphate by the ascorbic acid method (SM 4500-PE, PDF), and making the antimony potassium tartrate reagent. Standard methods uses $\pu{1.3715 g}$ of $\ce{K(SbO)C4H4O6 * 1/2 H2O}$ per $\...
2
votes
0answers
144 views

Why is it difficult to measure the pH of environmental water samples accurately (near 7)?

I've read in several places (edit: 1, 2, 3, 4, 5, 6, 7, 8. 9, 10, 11, 12) that there are many practical factors that make accurate pH measurements of roughly neutral environmental water samples more ...
2
votes
1answer
91 views

Finding formula of hydrated potassium chromium(III) sulfate through experimentation

I'm in Year 13 and this is a past paper question which I don't have a mark scheme for and I'm confused on the chemistry. Hydrated potassium chromium(III) sulfate has the formula $\ce{KCr(SO4)2.xH2O}...
1
vote
0answers
312 views

Possible Method for Testing Ammonia (and Nitrite/Nitrate) Concentration in Water

I am designing an automated system testing device for my high school's aquaponics club. We need to test for a number of ion concentrations, including ammonia and nitrite/nitrate. In my research, the ...
2
votes
1answer
2k views

How would I measure the dissolved carbon dioxide content of a liquid (water to start with)

I would like to measure the dissolved carbon dioxide content of a sample of water. I was thinking that conductivity might change with carbon dioxide level, and also pH. I would like to have the ...
5
votes
2answers
1k views

Minerals in water solidify when heated?

Is it possible for minerals in drinking water to solidify when high temperatures are applied? The minerals in mind are: iron, copper, aluminum, magnesium. Background: I have small, brittle, darkish ...
4
votes
1answer
184 views

Comparing Methods of Determination of Dissolved Oxygen Content in Water Sample

I am currently doing an IB Chemistry Individual Investigation on dissolved oxygen in water samples by using Winkler method. However, my teacher suggested that I have to use oxygen probe as a standard ...
2
votes
1answer
248 views

Colorimetric test to measure dissolved oxygen in salt water

Are there any simple colorimetric tests for measuring the dissolved oxygen in salt water, which do not involve titration like in Winkler method ? i.e. Are there any chemical reagents, which when ...
0
votes
1answer
92 views

Determining the amount of chlorine in a swimming pool

I need to determine the amount of chlorine in a swimming pool. How do I get started? What kind of experiment would I need to carry out? What equipment would I need for this experiment?
1
vote
1answer
599 views

Fluoride Color Reaction

I am trying to find visual ways to demonstrate water contaminants. For example, chlorine reacts to N,N-diethyl-p-phenyldiamine (DPD), forming a magenta color. The chemical doesn't need to be accurate, ...
0
votes
1answer
151 views

Quantifying Ascorbic Acid in Soft Drink

I have access to a GC/MS, FID, and a spectrophotometer. My first thought was to derivatize with trimethylsilylating agent, then run it by GC. Unfortunately the water is problematic. Heating it is ...