Questions tagged [experimental-chemistry]

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 field of research.

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27 views

Order of adding reactants on growth of Cu

I am reading the following paper which details the steps to control growth of Copper. They fabricate Copper powders from $\ce{CuNO3, NaOH, and C6H8O6}$. Specifically, in this paper they add the sodium ...
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1answer
88 views

does stirring honey make it less viscous? [closed]

After making some research, I found that crystallized honey does get less viscous as we stir it, so is it the same thing with pure honey or not? and also if not could we use the Zahn cup experiment to ...
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2answers
110 views

How to determine the iron content of a screw?

In Analytical Chemistry, I was asked to determine the iron content of a screw. I thought it could be solved in the following way: Treat the screw with a solution of sulfuric acid or hydrochloric ...
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1answer
1k views

Main industrial method for producing ethyl ethanoate (acetate)? [closed]

I am aware there are various methods, however, which is most prevalent in industry? Researching on Google has indicated Fischer esterification or Tishchenko reaction and other versions. Which is most ...
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1answer
46 views

can i synthesise Bis(tri-tert-butylphosphine)palladium(0) from Sodium tetrachloropalladate and tri(t-butyl)phosphine [closed]

can i synthesise Bis(tri-tert-butylphosphine)palladium(0) from Sodium tetrachloropalladate and tri(t-butyl)phosphine if so how do i isolate the product
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1answer
575 views

DIY Hand Sanitizer Clumping [closed]

Hand sanitizer is impossible to find around me and I have 4 family members who are essential and not around a sink or soap during their work day (delivery drivers), and they are out. I make a lot of ...
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1answer
30 views

Procedure vs. synthetic method?

I am genuinely confused on the difference between a procedure/flow chart and the synthetic method for a lab report and what exactly a synthetic method includes, and I can't find any information online....
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1answer
126 views

Cooking IN CO2 gas? [closed]

Quick theoretical question: What if I replaced water with dry ice in my pressure cooker? Assuming I used a calculated amount to prevent an explosion... Would It be able to cook? Would it dehydrate ...
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95 views

Why is the experimental pH of vinegar (acetic acid) so much higher than expected?

I bought some sodium hydroxide on Amazon and went about titrating solutions I make with it. As I'm an amateur chemist at home, I have limited tools. A pad of paper, some 5% acetic acid vinegar, and ...
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1answer
155 views

What is the relative rate of diffusion of ammonia to hydrogen chloride, both in gaseous states? [closed]

I encountered this problem during an assignment: I answered it as C, but the assignment grader marked it as wrong and indicated that A is correct. I asked another instructor about it and gave me a ...
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1answer
92 views

what catalyst to use for the reaction between AgNO3 and NaCl? [closed]

What is the best catalyst to use for the reaction between AgNO3 and NaCl that would result in a change in activation of energy so therefore more precipitate formed. Please give me the ways I can ...
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1answer
86 views

How can I make AgNO3 more basic? [closed]

Is there anything that I can add to the AgNO3 solution that will make it more basic without forming a precipitate such as reacting with OH or HCl? Please be more specific and give an example.
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1answer
216 views

Significance of shapes of Conical flask and Kjeldahl flask

What is the practical significance of the shapes of conical flask and Kjeldahl flask?
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3answers
100 views

What is the best way to make a substantial amount of soot in a high school laboratory?

I need to make about 50 grams of soot (carbon black particles) in a high school laboratory. What would be the best way to do this? The purpose of needing 50 grams of soot is because I would like to ...
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1answer
92 views

How to store small amounts of gas

I need to store small amounts of gas. I already saw devices that look similar to the image below, but I don't know how they are called. Does someone here know how these devices are called? I am also ...
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1answer
354 views

Preparation of potassium cyanide from potassium ferrocyanide via HCN

Does anyone have any experience with the preparation of potassium cyanide from potassium ferrocyanide via $\ce{HCN}$ method? I did some math and am going to proceed eventually, any advice would be ...
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1answer
67 views

laser diode problem [closed]

I'm a student studying chemistry, i'm working with diode laser to look at emission spectra for certain complexes. i'm using integrating sphere as my setup, when i use the 405nm diode laser output of 4....
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2answers
235 views

The burning candle - rising water experiment

This is a classic experiment. On a plate with a little water place a candle and light it. Place a drinking glass over it. The light goes out while sucking up the water. At least two things happen: ...
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1answer
45 views

Is it appropriate to call this material a hybrid composite? [closed]

The material I've synthesised is made up of two primary parts at a 1:1 ratio: Part 1: agar, glycerol, water. Part 2: polyurethane resin. The agar mixture on its own was too soft, so I added the ...
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3answers
1k views

How to control current and voltage in electrolysis

I am doing an experiment that aims to determine if the rate of electroplating changes with the temperature. I am using a copper rod, a solution of copper(II) ions and a neutral rod to be coated. I ...
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2answers
134 views

Particle size vs dissolving rate of sucrose

I’m required to make a lab with this information only (particle size vs dissolving rate of a solid (molecular covalent compound-sucrose)? so far what I’m thinking is using three different kinds of ...
3
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1answer
200 views

Why does the test tube face downwards in gas production?

In the preparation of $\ce{NH3}$ from $\ce{NH4Cl}$ and $\ce{Ba(OH)2}$, my teacher said that when heating the test tube, the test tube faces downwards as opposed to upwards. Why is this so? Wouldn't ...
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1answer
72 views

How does one determine whether a chemical requires hazardous waste disposal?

It is pretty easy to find information about the actual hazards of a chemical in the SDS, but I have been struggling to sort out which classifications require that the compound be handled differently, ...
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1answer
113 views

Is there any collection of charge density maps for small molecules? Any good data at all?

Despite wide variety of existing experimental methods producing electron/charge density maps, I failed to find a good dataset of experimental data for small (1-3 atoms) molecules. There are datasets ...
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2answers
56 views

What is meant by position 5' or 3' [closed]

I'm a self-learner that likes to keep up with current research. However, I can't find what is meant by expressions such as 5' or 3' positions on chemical structures. But , in particular, what is meant ...
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1answer
54 views

The rate of change in pH v.s Temperature

I have somewhat established that there is a linear relationship between change in pH of carbonic fizzy drinks over time. I also realise that the pH increases linearly faster for the same carbonated ...
2
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1answer
301 views

Why is absorbance in UV-VIS spectrometer negative even after calibration?

I was collecting data to plot a calibration curve using pure beta-carotene sample. Prepared 5 different concentrations of beta-carotene dissolved in methanol. Pure methanol was used as blank. However, ...
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2answers
431 views

How does pH of soda drink vary with time

Basically I have done an experiment where I measure the pH of my soda drink at a specific temperature over $\pu{45 min}$. At every temperature, the $\mathrm{pH}$ of my soda drink increases, but much ...
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0answers
27 views

Why does peak decoupling occur in H-NMR spectra?

For example, when we analyze the conversion of some chemical compound, certain characteristic areas tend to decrease (ok). However, why can a peak (i.e., one peak) generate smaller peaks (i.e., more ...
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2answers
796 views

Reaction between copper (II)chloride and aluminium foil [closed]

When I reacted copper chloride and aluminum foil instead of getting the brown color I got green color. Can anyone share their procedure where the experiment actually succeeded?
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0answers
59 views

How to determine the pH of citrate buffer system

I used this table (http://microscopy.berkeley.edu/Resources/instruction/buffers.html) to make a citrate buffer system. The Pka value is 6.4, and I multiplied the solution by ten to make a larger batch....
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1answer
148 views

How is silica gel made? [closed]

How is silica gel prepared from sand (after extracting it). How many ways can it be used? Is there a way to make it without an oven?
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1answer
118 views

Fractional index in a chemical formula of metal oxide

I have just read an article in which they used $\ce{WO3}$ and $\ce{WO_{2.9}}$ as precursors, whose objective was to form $\ce{WS2}$, in an atmosphere of argon by CVD. In one boat there is the powder ...
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1answer
101 views

Sodium hydride 60% dispersion in mineral oil [closed]

I've got a bottle of sodium hydride 60% dispersion in mineral oil. It's not "in mineral oil" it's just powder with an oil coating. I'm using it in an inert reaction, is there a way to remove the oil?
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1answer
95 views

Is there a list of must-have columns for LC-MS/MS used in biochemistry/clinical lab setting?

Considering a wide variety of chromatographic columns used for (U)HPLC based on phase type (normal or reverse); column dimensions (geometry, length, inner diameter); particle material $(\ce{SiO2},$ $\...
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1answer
616 views

Decomposition reaction of tin(II) nitrate [closed]

What are the products formed when $\ce{Sn(NO3)2}$ is subjected to high temperatures? I searched over the internet but I didn't get any satisfactory answer.
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29 views

To get clear plasma out of a minute particle (such as fibrin), is it necessary to vortex sample before centrifugation? [closed]

I'm going to analyse plasma samples that contain a lot of fibrin. It is necessary to centrifuge the samples to be able to pipette the plasma. After the samples are centrifuged I can't vortex them ...
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2answers
58 views

Reproducibility and Standard Deviation [closed]

Would a set of chemical data with a relative standard deviation of 0.6% or 20% be more reproducible? My reasoning is that because it's easier to make mistakes and have a wide range of data, the 20% ...
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1answer
221 views

why is water not compatible with lewis acids in a friedel-crafts alkylation [closed]

I know that it destroys the lewis acid character but that doesn't tell me anything.
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2answers
979 views

How are reaction enthalpy and entropy affected by temperature

The equation for Gibbs Free Energy demonstrates how the standard change in Gibbs Free Energy for a reaction is affected by temperature. $$\Delta G^\circ = \Delta H^\circ - T\,\Delta S^\circ$$ ...
2
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1answer
439 views

Fehling's solution turning yellow and then black?

While testing for formaldehyde (an aldehyde), I added Fehling's solution to the sample and let the test tube simmer in a water bath for some time. I returned ~15 minutes later to see a black/dark grey ...
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0answers
15 views

Ammonia Vapor Absorption Refrigerator

I am working on fabricating the icyball system. I am planning to charge it with the help of convex mirrors. Whether it is necessary to create a vaccum inside the refrigeration closed cylinders before ...
4
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0answers
40 views

membrane for a reverse osmosis desalination experiment

We are second year cram schoolers , we are currently working on a project tackling water desalination by reverse osmosis and are required to do an experience. During the process, we encountered some ...
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0answers
38 views

How to assign initial and final states of iodine transitions in its spectrum?

In an experiment, I gently heated iodine crystals to create vapors and then observed it absorption spectrum with a spectrometer. The temperatures throughout were moderate (maximum $40^\circ\text{C}$). ...
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0answers
51 views

Observing bands which I shouldn't be!

I performed the iodine spectrum experiment to observe vibronic transitions. I heated the iodine crystals to produce vapors (at a little above room temperature) and observed absorption spectrum with a ...
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1answer
40 views

Why does Calcium (specifically Calcium Carbonate) inhibit the Citrate buffer system?

Is it because citrate chelates calcium and then is unable to react with other chemicals being added? If so can someone explain this reaction to me, or if not provide what the reason is? If anyone has ...
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2answers
238 views

Figure out how many deuterium atoms in a 3 microgram ice core sample

I'm in an introductory Chemistry class and ran into a Pearson problem, that no-one in our class including our professor has been able to truly figure out. I know the solution is $4.69 \times 10^{13}$...
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42 views

How will the dielectric constant of water change when ethyl acetate is added?

How will the dielectric constant of water change when ethyl acetate is added? The $\mathrm{p}K_a$ value of weak acids in aprotic solvents will be lower than in protic solvents because the dielectric ...
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1answer
166 views

Independant variable for Asprin pill titration with NaOH solution [closed]

I am assigned to do an independently designed chemistry experiment for school. I want to do titration of Aspirin pills with NaOH solution using Phenolphthalein as indicator. I am struggling to find ...
2
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2answers
64 views

Lab goggle recommendations?

I'm taking my first chemistry class with a laboratory component this quarter. My first laboratory session was earlier this evening (observing simple metathesis reactions). While I found the lab work ...

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