This tag should be applied to questions relating to the theory, design, techniques or performance of chemical experiments. This includes but is not limited to theoretical structures, expected products, thermal calculations, and empirical analysis. Additional tags should be applied to narrow down the ...

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Preparing Saturated Carbon Dioxide

I'm doing a chemistry lab where I'm collecting data to create a solubility curve for carbon dioxide at different temperatures. I'm using carbonated water and my concern is that, by heating or cooling ...
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1answer
21 views

aluminum hydroxide as an electrolyte

A friend and I recently produced some aluminum hydroxide, $\cf{Al(OH)3}$ for a project, and we wondered how it functions as an electrolyte. We know it has a low conductivity and solubility, but we ...
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19 views

Why does the activation enthalpy of ester hydrolysis increase with an increase in alcohol-chain length?

(Particularly concerning acid hydrolysis) Is there some sort of chemical reason as to why with increasing alcohol-chain length, there is also an increase in the minimum energy needed to cause the ...
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0answers
20 views

decomposition of h2o2

According to the decomposition of 3% hydrogen peroxide, if 2cm^3 of h2o2 is used, then 3 x 10^-5 mol of 02 should be produced. However, we needed to find the theoretical yield so we conducted an ...
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1answer
17 views

How to calculate the volume of oxygen in a reaction between hydrogen peroxide and bleach using this apparatus

I know that the reaction between bleach and hydrogen peroxide produces oxygen but using this apparatus and information I need to state how to calculate the volume of oxygen released. From my initial ...
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1answer
35 views

Test for Fe2+ ion in salt using potassium hexacyanidoferrate(III)

It's given in my book that $\ce{Fe^3+}$ ion reacts with potassium hexacyanidoferrate(III) to give brown colour. $$\ce{Fe^3+ + [Fe(CN)6]^3- -> Fe[Fe(CN)6]}$$ Both the reactants have the same ...
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0answers
22 views

An alternate purification process for sugar separation form bee honey?

Bee honey contains 75% sugars (Fructose, Glucose, Maltose, Sucrose and others), some water and low amount of different compounds (up to 5%) Wiki. Basic purification is done by addition of phosphoric ...
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11 views

Mixed to chemicals with corresponding percentage resulting to a PPM, how does each element contribute to the total PPM? thanks! [closed]

For example: 6 grams of CaNo3; Calcium 60% & Nitrogen 40% 8 grams of Kno3; Potassium 70% & nitrogen 30% BOth mixed together in a distilled water resulting to 1000 PPM. HOw much did the 3 ...
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13 views

Is it possible to quantify the effects of a chelating agent?

If one wants to see what compound is a more effective chelating agent, how does that get measured?
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0answers
22 views

What are the methods used to measure the concentrations of these anions?

Chromate and dichromate anions has the following equilibrium in acidic solution: $$\ce{2CrO4^2- + 2H3O+ <=> Cr2O7^2- + 3H2O}$$ How can one experimentally measure the concentration of each ion ...
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4answers
608 views

How do I control the temperature in an experiment?

If one were to adjust the positive temperature in an experiment, they would use a heating plate, or a stovetop. How would one adjust negative temperatures in an experiment? (Not keeping the ...
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2answers
137 views

Why do we scratch the walls of test tube in test for Magnesium or Calcium basic radicals?

In test for Calcium ion (Group V) , we add Ammonium Carbonate in presence of Ammonium Hydroxide and then white precipitate (of CaCO3) is formed which is dissolved in Acetic Acid and then reacted with ...
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0answers
38 views

How to differentiate Zn 2+ and Al 3+ on the result of blue lake test

While performing test for basic radical in analyzing a salt qualitatively. I found out that the salt gave the blue lake test and since we were taught that only Al 3+ gives blue lake test, I thought it ...
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1answer
32 views

Color imparted to flame and color of coordination compounds

When we heat a ionic substance/compound, the ionic bond gets weakened and the metal is ionized. Is the color imparted to the flame due to absorption of light? i.e. Do we see the remaining wavelengths? ...
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0answers
8 views

how much of each solution do you need to prepare 500mL of a reagent that contains ..? [closed]

Given stock solution of glucose (1000mM), asparagine (100mM) and NaH2PO4 (50mM), how much of each solution do you need to prepare 500mL of a reagent that contains 50mM glucose, 10mM of asparagine and ...
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1answer
17 views

Significant figure rules when plugging a value into an equation or formula

I have not been able to find an answer to what may be a silly question so I am asking it on here as a last resort. If I am to plug in say a number like 14.0 Celsius into the formula that solves for ...
3
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0answers
42 views

Could any constituent of normal human urine produce a false positive in a Kastle-Meyer test for presence of blood?

From my understanding, one forensic test for the presence of traces of blood at a crime scene is (or was) the Kastle-Meyer test. Doing some research, I understand that in the test, hemoglobin reacts ...
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1answer
43 views

What chemicals react with alcohol?

I am curious if there is any chemicals that react with alcohol to either produce a visible colour change or an odour someone could smell.
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2answers
45 views

My easy Styrofoam experiment is not working properly

Why doesn't gasoline or paint thinner melt through Styrofoam when I try it yet there are videos of others melting Styrofoam in gasoline and paint thinner? Is there something I am doing wrong? This is ...
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0answers
12 views

Yield reporting in methods section of report

I'm in an integrated laboratory course at university that combines all the disciplines of chemistry that we have here. I was instructed to place the yield in the methods section of the report by my ...
3
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2answers
73 views

Why do you need to convert copper (II) hydroxide to copper (II) oxide before converting to copper (II) sulfate?

This is the protocol for a practical class I once took. The idea is that copper nitrate is converted to hydroxide, oxide, sulfate and then finally solid copper. I know that $\ce{CuO(s) + H2SO4(aq) ...
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1answer
13 views

Can I use fluorescence microscopy with a solution of hydrogen peroxide?

I want to use microspheres which have been dyed with a fluorescent dye for fluorescence microscopy in a solution that has a 1-5% concentration of hydrogen peroxide. Is this possible or will the ...
5
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1answer
107 views

How to extract water from a solution in formamide

I'd like to determine the water content in a sample without buying an expensive machine (like Karl Fischer titrator). So I'd like to measure the water volumetrically. I've chosen formamide to dissolve ...
2
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1answer
40 views

How can I make my yeast experiment more chemistry-oriented? [closed]

For a school chemistry design lab I tried to find the optimal sugar concentration for fastest yeast fermentation. I put the same amount of yeast and sugar water solutions with different concentrations ...
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0answers
20 views

Charge:ionic radius ratio

can someone please explain what the charge to ionic radius ratio of a metal hydroxide would mean for its solubility. As in would there be a trend e.g. as the ratio gets larger the solubility product ...
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0answers
25 views

KMnO4 Oxidation of Methyl Group Attached to Nitrogen

Is it possible for a methyl group directly attached to a nitrogen atom in a non-aromatic compound $\left(\ce{-N-CH3}\right)$ to be oxidized using $\ce{KMnO4}$ in acidic medium to form a corresponding ...
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0answers
27 views

Soluble or insoluble?

In the picture attached here, is the compound in water soluble or insoluble? I get confused while identifying solubility of a solute in a solvent when a situation like this arrises. The crystals of ...
5
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1answer
59 views

Electrolysis of water for demonstration: ideal electrolyte for safety, stability, conductivity, and ease of maintenance

I'm developing a system for educational purposes where electrolysis of water takes place. The aim is to practically show how electrical energy can be converted to mechanical, by electrolyzing water, ...
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0answers
28 views

Non-destructive solvents for cyan-salts

What dissolves cyan-salts (NaCN and KCN) without destroying them the way water does via hydrolysis? I have to make my own cyan-salts, so they're somewhat precious to me. Every time I have to ...
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1answer
241 views

What is the structure of iodide of Millon's base?

In qualitative analysis, $\ce{NH4+}$ ions are confirmed using Nessler's reagent:- $$\ce{NH4+ + 2[HgI4]^{2−} + 4OH− → HgO·Hg(NH2)I ↓ + 7I^{−} + 3H2O}$$ The brown precipitate formed is called ...
3
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0answers
28 views

Why is contact angle higher when I let the glass to be dried in silan solution?

I've read in literature that the silanization reaction is completed in a second. However, I realized an interesting thing; after one hour that my cleaned glass beads are deep coated in a silan bottle ...
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0answers
34 views

How to test reactions under pressure?

This is my first time posting here, so I'm not sure if I'm doing it right. Anyway, I am trying to test chemical reactions, more specifically reactions between an acid and a base, at different levels ...
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1answer
17 views

How to finish silanization process correctly?

I have some 2mm glass beads and I'm doing silanization on them. For doing that, I have a small bottle that I fill 1/3 with glass beads and then pour silan solution on them and shake well. However, ...
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1answer
39 views

Compound Formation and Properties [closed]

A student was given a mixture of powdered iron and sulphur. He was told to heat it and answer the following: What is the colour of the compound formed? Write the effect of magnet on it. What is the ...
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1answer
24 views

Desorption instead of adsorption from solution using activated charcoal

I was just trying to see the effect of concentration on adsorption in solutions, i.e. I was trying to verify the Freundlich isotherm. I used oxalic acid and a batch of homemade activated charcoal ...
1
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1answer
59 views

How can I make a fairly saturated copper (II) sulfate solution by heating?

I have an investigation to do for my chemistry class. I'm looking at copper complexes and using ammonia to create a precipitate in the copper (II) sulfate solution, then redissolving the precipitate ...
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0answers
19 views

Why did I get different results in two very similar silanization cases?

I silanized two glass surfaces: For the first one, I used Octadecyltrichlorosilane, 95% but since I finished the first bottle, for the second test I got ODTCS 90%. However, the results that I got from ...
3
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1answer
38 views

How durable is a silanized surface?

I have two questions regarding silanization: 1) How durable is a silanized glass surface? (i.e. How long a silanized surface can be kept without any change in its wettability or contact angle?) 2) ...
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1answer
196 views

Textbook chemistry vs Real life chemistry and impurities

Long ago when I took chemistry courses in high school and lower, chemistry seemed so simple and elegant. All equations and exercises involved pure elements, pure compounds, with a very clean ...
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0answers
36 views

What is the best material for my particles?

I'm investigating collision of a particle and a water droplet ($v_\mathrm{drop}=1~\mathrm{m/s}$, $v_\mathrm{particle} \approx 8\ \mathrm{m/s}$, $D_\mathrm{d}=2.8\ \mathrm{mm}$, $D_\mathrm{p}=2.0\ ...
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0answers
32 views

In silanization, how to clean kerosene from glass surface completely?

I'm doing some silanization experiments using kerosene to dilute the silan solution. For instance I use a mixture of 10% silan in kerosene. However, after several tests I realized that I cannot ...
2
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0answers
32 views

Methods of dissolving a gas into a liquid

I know that carbon dioxide is dissolved into water in a soda fountain using a sort of a tubular manifold that mixes the water with pressurized carbon dioxide as it goes through it. Is that the best ...
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1answer
57 views

What does radiofrequency really do in NMR & MRI?

In NMR, the protons’ frequencies are affected by the magnet which makes them precess around its magnetic field so now all protons will have different frequencies according to their environment ...
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1answer
30 views

Why did I get these inconsistent experimental results in silanization?

I used a 50% wt mixture of Tetraethylorthosilicate + Kerosene for silanization of some glass plates with different treatment times (from 1 sec to 35 sec). However, the contact angle(CA) that I got ...
6
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0answers
94 views

Mixing naphthalene, formaldehyde and sulfuric acid (Marquis reagent + naphthalene)

Excuse me if this a dumb question but it has haunted me for years. Back in my old school days I mixed naphthalene, formaldehyde and sulfuric acid in a mad attempt to make ...
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0answers
13 views

How to do pre-treatment on surface and how to clean the glass surface after silanization?

By Silanization, I want to treat surface of some spherical glass beads. Each bead is supposed to be shot in a particle launcher (like a bullet from a gun). I have some detailed question for the ...
4
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1answer
45 views

Using results of current experiments in silanization, how to achieve a higher contact angle?

I've done several silanization tests with different solutions and here is a brief of my results: DichloroDimethylSilan: Advancing=90, Receding=56 ChloroTrimethylSilan: Adv=91, Rec=70 ...
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1answer
56 views

Three general questions in silanization of a glass surface

For silanization, I put a glass slide horizontally and pour the silan solution on it to cover the glass surface. Then I leave it for a specific time and then wash with water and acetone. I have ...
2
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0answers
29 views

Why we have mass of adsorbent in Freundlich equation?

In Freundlich equation why we have $m$ the mass of adsorbent. I mean it is surface chemistry and on the surface of adsorbent the adsorption takes place so why we have mass of adsorbent in that ...
5
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1answer
59 views

What is the chemical test for identification of benzophenone?

How to identify that a unknown compound is benzophenone? My working:- First I added 2,4- DNP(2,4-Dinitrophenyl hydrazine) to the compound. Yellow-orange crystals were formed which indicated ...