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.
1,426
questions
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1answer
28 views
How to make foggy and cloudy plastic fully transparent?
I used sandpaper of different grits to sand the surface of plastic. The surface is smooth but it looks dull after sanding. I read that one could use toothpaste to remove the foggy look but it did not ...
-1
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0answers
18 views
What happens when zinc is added to dilute tetraoxosulphate(iv)and why [closed]
Zinc was added to dilute tetraoxosulphate(iv)and an exothermic reaction took place.bubbles of gas evolved but eventually the evolution stopped.How does the temperature of the mixture change during the ...
-3
votes
0answers
18 views
Chloropropane was hydrolysed by an aqueous potassium hydroxide solution [closed]
Can anyone help me with this question please. I couldn’t write and I post the picture which included my question. It has six part to answer this question.
0
votes
1answer
32 views
The quantum mechanics behind periodicity of elements
Especially in high school/first-year undergraduate chemistry courses, we learn with great dedication the periodicities along groups and periods. There are various useful and interesting trends.
I ...
0
votes
1answer
59 views
Why don't conc HNO3 react with Al2O3,Cr2O3 and Fe3O4?
The reason for conc. $\ce{HNO3}$ not reacting with aluminum, chromium and iron was given as the formation of protective oxide layer. But the oxides of these metal are amphoteric($\ce{Al2O3,Cr2O3}$)/...
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0answers
29 views
Is this gif possible - an ice cube solidifying liquid? What is the science behind this? [closed]
I would like to know the science behind this gif. I have searched the internet to look for a similar experiment attempt but failed. Is there science behind this or is it just a computer edit? Thank ...
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0answers
22 views
?Arrhenius graph is not a straight line. reason? [closed]
The rate of formation of the product of a reaction gives no
Arrhenius bar chart (k versus 1 / T concave to 1 / T,
where the activation energy is lower to higher
temperatures). Justify the specific ...
0
votes
0answers
24 views
Doubt in a nomenclature for equilibrium constant
Why is there $H,N$ and $CO$ attached to the suffix of equilibrium constants? Particularly how to use these as suffixes? Nothing can be extracted from the reaction. There are many $H,N$ and so on like $...
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0answers
26 views
Calculate the pressure exerted by 0.0153 moles of CO2 gas in a container of 1.467 L at 20.0C [closed]
a) Calculate the pressure exerted by 0.0153 moles of CO2 gas in a container of 1.467 L at 20.0 °C.
b) What is the volume of a 15.0 g sample of propane (C3H8) gas at Standard Temperature Pressure?
...
8
votes
1answer
423 views
Photochemical reduction of benzophenone: why inverted flask?
I've come across an interesting protocol for photochemical reduction of benzophenone to benzhydrol (diphenyl methanol) with sodium alcoholate in alcohol, the 2nd protocol in https://prepchem.com/...
-1
votes
0answers
13 views
how many molecules of strontium carbonate are contained in a sample of strontium carbonate, which has the mass of 605.28g [closed]
the main ingredients for fireworks are a fuel, a substance to react with the fuel
(an oxidizer), a material to hold all of the chemicals together (a binder), and chemicals for special effects. ...
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0answers
21 views
0
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0answers
40 views
How reliable is spectrometry in the determination of the oldest material Startdust?
After reading one of the latest findings by scientists, Stardust was considered the oldest material on earth. However having not much of an experience with chemistry, I was intrigued upon how ...
-1
votes
1answer
38 views
In the Gold Foil experiment, did Ernest Rutherford's alpha particles hit the same spot every time or did he direct the emitter to different spots?
When reading and learning about the gold foil experiment, the alpha particles mostly go straight through the gold foil and some get deflected or bounce back but it doesn't say anything about the ...
1
vote
0answers
24 views
Standard practice for keeping salts dry
I should point out first that I'm not a chemist, but I'm currently doing a little bit of chemistry; this should clarify that I don't have formal training in a chemistry lab (other than some basic chem ...
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0answers
21 views
Question about reactive chemicals that make the other change color for a limited period of time when exposed? [closed]
Are there non-toxic chemicals that can be mixed with paint and used to paint two surfaces. When exposing one surface painted with one chemical and paint is exposed to another item painted with a ...
1
vote
1answer
31 views
BPS & BPA treatment with 80% Ethanol
Background: BPA and BPS (Bisphenol A/S) are artificial estrogens and therefore toxic chemicals for us. They are used in the coating of thermal paper. Thermal paper is used to print in-store receipts. ...
2
votes
0answers
23 views
Flux a specific concentration of a tracer constituent of a gas
I need to flux 250 ppm of CO2 at 1000 ml/min.
I have a gas system with a tank containing CO2 (CO2 at 5000 ppmvol, Oxygen 21%vol and Nitrogen the rest), connected with a mass flow controller (MFC1, ...
1
vote
0answers
19 views
What is the best way to clean Lovibond tintometer quartz cuvette used for oil?
I work in a laboratory where we regularly check edible oil color by using a Lovibond colorimeter. Some people suggested me to wash the quartz cuvette using soap solution.
But I am thinking about ...
5
votes
0answers
61 views
Why does my drierite turn bright bright blue, instead of pink?
Drierite a brand name of a commonly-used, calcium sulfate-based dessicant in many chemistry labs. The lab I work in has a dessicator box we use to store hygroscopic materials. It isn't a a true dry ...
0
votes
2answers
151 views
What is the essence of chemistry? [closed]
I am an engineering student who loves physics but didn't quite enjoy chemistry.
a. When I was in high school chemistry to me was something not as inspiring as physics but in which I couldn't solve ...
1
vote
0answers
20 views
Is it possible for graphite which has shed off metal rods during water electrolysis to bond with the hydrogen being produced to form hydrocarbons?
I recently conducted a simple experiment for school involving the electrolysis of water.
I changed the concentrations of an ionic compound to determine its effect on the rate at which the products of ...
0
votes
1answer
72 views
Is it possible to heat up water using chemicals? (Meaning no outside source of heat like electricity, or gas) [closed]
I am asking in terms of heating something small like a 10oz cup of water with it also being safe to consume. It would have only need to heat the water for around 1-2 hour(s).
1
vote
1answer
45 views
Why are some weak acid equilibrium approximations invalid in very dilute solutions?
Using two approximations for the dissociation of a weak acid, we can write
$$K_\mathrm{a}= \frac{[\ce{H+(aq)}]^2}{[\ce{HA(aq)}]}$$
One of these two approximations we use is that the concentration of ...
1
vote
3answers
71 views
Need reactants for a rocket [closed]
I am doing a project in chemistry at the moment to build a rocket out of materials that can be easily bought and that react strongly to create thrust.
I was wondering if anyone knew a good chemical ...
0
votes
0answers
12 views
Difference in collision cross-section obtained by measurement method
I have a simple question of Physical Chemistry, but I don't know the answer.
We can find collision cross-section(σ) through experiments in three ways.
first, diffusion flux experiment. diffusion ...
0
votes
0answers
25 views
Mechanism for Lucas Test [duplicate]
In the mechanism for Lucas' Test for Alcohols, I am reading two different types. One says the first step is the abstraction of a proton from HCl, but on other references, I also see that the first ...
0
votes
2answers
57 views
Effect of dilution on weak acids pH [closed]
My textbook has a question which says what would happen to the pH of a weak acid if it is diluted with water. The answer is its pH would decrease.
My teacher’s argument is that it would indeed ...
0
votes
1answer
69 views
Combustion of NaCl(aq) when testing conductivity
In a experiment that dealt with electric conduction of many concentrated solutions, NaCl(s) created an unknown, to me, substance after adding a drop or two of water. Furthermore, it isn't the reaction ...
1
vote
0answers
55 views
Is Porphyrin Planar?
I have been looking at this diagram from quite some time, I know the 18 pi electron cycle that forms porphin(e) is definitely planar but what about the whole molecule?... The Nitrogen's act as a ...
3
votes
2answers
187 views
Can nitrous dioxide develop when copper and dilute nitric acid react?
When doing an experiment in the laboratory with copper, dilute nitric acid and finally hydrochloric acid, the first reaction between copper and dilute nitric acid should end in nitric monoxide, cupric ...
1
vote
0answers
22 views
How to extract limonene from the orange peels?
What is a reasonable procedure to extract the orange essential oil from the rinds? I thought this would be a common experiment.
Here's what Wikipedia had to say, they identify the essential oil as ...
1
vote
1answer
52 views
Does using same calibration curve for chemical analysis introduce correlation in sample error/uncertainty values?
I am using a hypothetical case to explain my question
Let us consider a chemical analysis method A (using a certain instrument), which is used to quantify the value of a particular species b. ...
1
vote
0answers
25 views
Help on Research Proposal [closed]
I am a freshman majoring in chemistry. I am aware that one of the tasks required in this field is extensive research, and I am encountering a big problem. I am lost as to how to think of a plausible ...
0
votes
2answers
66 views
Sonication to purify solid product- the crude product just disappeared
I am forming Fmoc-valine-citrulline dipeptide, and below is the literature protocol I am following (from Bioconjugate Chem 2002, 13 (4), 855-869):
Formation of Fmoc-Val-Cit
Fmoc-Val-OSuc (...
1
vote
1answer
44 views
Equivalence point of titration of Sodium carbonate
The pH at the equivalence point of titration of $\ce{Na2CO3}$ solution with $\ce{HCl}$ is around 3.7, as shown in this titration curve:
At this point, the following reaction is completed:
$$\ce{...
0
votes
0answers
21 views
Why hydrogen gas tube produce hydrogen atomic spectrum
To measure the atomic hydrogen spectrum people often uses hydrogen gas tubes as light source.
Since the gas in the tube is the molecule $H_2$ , why we obtain the spectrum of atomic hydrogen?
My guess ...
0
votes
0answers
57 views
Why does B12H12 Borane not exist? [duplicate]
Whenever I searched "$\ce{B12H12}$ Borane", I can't seem to find anything, and get met with only the dianion of $\ce{B12H12}$. Why doesn't $\ce{B12H12}$ exist on its own?
1
vote
1answer
79 views
When writing a paper should I describe the procedure thoroughly? [closed]
I have not written any article on a chemistry subject yet, and I want to use good practices from the start.
What I have noticed reading papers, is that a lot of times it is not specified the exact ...
1
vote
1answer
29 views
Is there an experimental way of measuring the critical concentration of pigment in paint?
With an assigned, generally paint-based, experimental project I've been looking up CPVC or critical pigment volume concentration in binders. CPVC defines the point of addition of pigments after which ...
0
votes
1answer
181 views
Can Anyone Explain the Mechanism of the Birnbaum-Simonini reaction?
When silver acetate reacts with iodine and $\ce{CCl4}$, it gives esters and 2 moles of $\ce{AgI}$ but when it reacts with iodine and lead acetate, why it gives alkyl halide, $\ce{AgI}$ and $\ce{CO2}$....
0
votes
1answer
50 views
Calculating the density of a magnesium sulphate solution
I am trying to calculate the density of a magnesium sulphate solution and came across this paper which determines an equation from experiment to do that. However, I am having trouble understanding the ...
2
votes
2answers
61 views
How do I prevent oxygen interfering when I prepare a FeCl2 solution from anhydrous FeCl2 powder?
I have a bottle of anhydrous $\ce{FeCl2}$ powder (from here; it is 98% pure and was kept in a glovebox after opening it for the first time to minimize reactions with oxygen) and want to make this into ...
0
votes
0answers
23 views
Weak acid titration curve [duplicate]
At the beginning of a weak acid titration curve (when titrated with a strong base), there is a sharp increase of pH before it levels out more due to the buffer solution that will occur. But why is ...
-3
votes
1answer
37 views
How does it affect the equilibrium expression if the concentration of any component remains the same?
I am a high school student and I am very confused in Equilibrium expression, My confusion is that "Why we don't write concentration of solids and pure liquids in equilibrium expression?" ...
3
votes
1answer
43 views
Difference in titration curves
In my titration curve for HCl being titrated with NaOH, the initial pH-value was plotted as 2.1 according to a pH-meter. When I found the equivalence point and calculated the concentration of HCl, it ...
1
vote
0answers
30 views
Bond dissociation energy for polar molecules
This formula relates to how Pauling determined the values for electronegativity for all the elements and how delta (if big) shows that the molecule is very polar. Delta being:
$\Delta =\Delta H\left(...
-1
votes
2answers
75 views
Can a weak acid react to give a stronger acid? [closed]
I was trying to understand why $\ce{AgCl}$ does not dissolve in $\ce{HNO3}$ and the reaction I could think of was something like this:
$$\ce{AgCl + HNO3->AgNO3 + HCl}$$
I could not understand why ...
0
votes
1answer
40 views
Viewing and capturing real time values of Electronic balance measuring instrument on television set and computer monitor larger screens [closed]
https://en.wikipedia.org/wiki/Weighing_scale
Is it possible to view and capture real time values of Electronic balance measuring instrument using wired, wireless,CCTV technology on television set or ...
-4
votes
1answer
43 views
Number of moles and Avagadro's number [closed]
Counting # of atoms don't match in rounding?
The total number of atoms contain in 1.0L as 1000g of liquid water must equal the total number of atoms contained in a gas released by 1000g of liquid ...
