Questions tagged [teaching-lab]

For questions regarding teaching in a laboratory setting.

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Does the side of filter paper matter?

A question has bothered me for quite a long time. I noticed some filter papers have a smooth side and a rough side. Does it matter (in theory) if I use the smooth side or the rough side for gravity ...
Richie12138's user avatar
3 votes
0 answers
57 views

Does real-world gas phase chemistry use "concentration reaction quotients" (K_c)?

As a theoretical chemist, my entire exposure to reaction quotients and equilibrium constants ($Q$ and $K$) is through thermodynamics ($\Delta G^\ominus = - RT \ln K_{eq}$ and so on). So as I started ...
Shern Ren Tee's user avatar
4 votes
1 answer
741 views

What is happening in experiment coating a copper coin with zinc and turning it to brass?

Today in class we did the "gold penny" experiment, where we put metallic zinc and a penny in a zinc chloride $\pu{1 M}$ solution at $\pu{100 °C}$, which caused the penny to turn silver as ...
anonymousaga's user avatar
1 vote
0 answers
73 views

Why isn't my sodium acetate demo working?

So I'm trying to do the sodium acetate tower demonstration that I've seen a ton of videos on. I don't have sodium acetate and I am making it from a liter of 5% distilled white vinegar and pure baking ...
NateL's user avatar
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5 votes
2 answers
390 views

Looking for terminology for when a hygroscopic chemical gets moisture in it

Scenario: A jar of zinc chloride (which is very hygroscopic) is left on a shelf in a chemistry classroom for several years. You open it and it is hard. What is the word to describe that? It was ...
Jessica Sargent's user avatar
2 votes
1 answer
737 views

how to improve self-constructed calorimeter (heat insulation)

Purpose: My purpose of this project is to use some environmental friendly material to construct calorimeter instead of using styrofoam. I tried: I use two different size test tube as my calorimeter(as ...
Chemist2020's user avatar
-1 votes
2 answers
298 views

Why did anyone invent the concepts of acids and bases? [closed]

I am home-schooling my son in first-year Chemistry, and I am struggling to teach Acids and Bases in a rewarding way. I am not new to Chemistry. I went to grad school in Physics and I even taught High ...
nineytoon's user avatar
1 vote
1 answer
104 views

Natural Sources for S-(-)-Limonene?

I'm interested in developing an undergrad organic lab that delves deeper into distillation/extraction, optical rotation and enantiomers. Our lab currently does a steam distillation extracting R-(+)-...
Jeff Gustafson's user avatar
-1 votes
1 answer
68 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 ...
Prashant Akerkar's user avatar
-1 votes
5 answers
252 views

What are practical examples of simultaneous measuring of quantities?

I am a maths teacher and I'm looking for practical examples of measuring quantities simultaneously, so that mathematically one needs to construct and solve a system of equations. I thought that in the ...
Geoff's user avatar
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-1 votes
1 answer
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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
Wesley Ng's user avatar
1 vote
1 answer
267 views

What is the correct term of a chemical formula for very large molecules if not just "chemical formula"? [closed]

I know that many molecules, wihch I as a non chemist, might define as "small" if their two dimensional diagram can be sketched on an A4 page, are often formulated; ...
user avatar
1 vote
0 answers
4k views

Why do we begin an experiment involving solutions of different concentration from the least concentrated solution?

Is there a particular benefit to start any kind of measurement with the least concentrated solution and then work my way up to the more concentrated solution? In one of my experiment, we measure the ...
Dennis lul's user avatar
3 votes
1 answer
5k views

Why does camphor sublimate?

I was doing a laboratory experiment the other day and they asked us to heat a beaker that contained camphor and to cover it with a watch glass with ice on it. I understand the crystallization ...
Patricia GC's user avatar
1 vote
1 answer
217 views

Is it possible to make polyethylene in a high school laboratory?

We learned how to make small amounts of ethene from ethanol using sulfuric acid. Is there a way to make a visible amount of polyethylene from that using materials I could get for a school lab? We can'...
Martin's user avatar
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1 answer
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How to effectively wash the precipitate or crystals on the filter and why?

My lab manual says that the precipitation on filter should be washed with a few small portions of the washing liquid. Why can't I just completely fill the filter funnel with the solvent instead of ...
andselisk's user avatar
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1 vote
0 answers
53 views

Limiting factor on Belousov-Zhabotinsky reaction

In the thin film Belousov-Zhabotinsky reactions (popular on Youtube/in chemistry demonstrations), concentric rings of different colors propagate across a petri dish for minutes to hours as the ...
Grover Cleveland's user avatar
0 votes
1 answer
47 views

Are the words "apparatus" and "equipment" synonyms? [closed]

Are the terms "apparatus" and "equipment" synonyms, within a chemistry or physics laboratory? If not, what are distinguishing factors?
Swaroop Chandra's user avatar
1 vote
3 answers
4k views

Should data tables be made in pen or pencil? [closed]

For a chemistry lab, I have to make a data table. Should data tables be written in pen or pencil? What is done in the real world of Chemists and why is it done in such a way?
John D's user avatar
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1 answer
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Making nylon experiment - Questions

I made nylon in a lab with these procedures - 1) Collect 30mL of sebacoyl Chloride dissolved in hexane 2) collect 30mL of 1,6-hexanediamine dissolved in water . 3) Transfer the beaker containing ...
user307640's user avatar
1 vote
0 answers
254 views

Wondering how I should have graded this question (freshman lab, about buffer capacity)

I TA the intro freshman lab course. In a lab about buffers and buffer capacity, the students were instructed to make 50 mL of a 0.1 total molar pH 6.70 buffer by dissolving solid $ KH_2PO_4 $ and $ ...
iammax's user avatar
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5 votes
2 answers
33k views

Why bother to standardize a solution?

I have been preparing lessons for some of my students about preparing acidic and basic solutions, and I keep finding pre-made labs in which the students "standardize a basic solution" by titrating it ...
Jesuspowder's user avatar
-3 votes
1 answer
929 views

How to remove hydrate from Fe(NO3)3 . 9H2O?

I am currently in a dilemma where I need to have pure Iron (III) nitrate, but I have Iron (III) nitrate 9 hydrate in order to do a lab experiment where I investigate voltaic cell. I am pretty sure the ...
idk wat else's user avatar
-2 votes
1 answer
1k views

What will Happen if p-nitrophenol is heated with HCl and then cooled?

When working in my Lab with p-nitrophenol ,I added some concentrated HCl and heated until it was fully dissolved. Then I cooled it in ice bath and found a white salt like compound which is not ...
Anwar Khan Tanveer's user avatar
4 votes
1 answer
4k views

How to remove sulfuric acid from sample

I have problem with my experiment. My experiment is acid hydrolysis of ethyl benzoate. The acid that I used is sulfuric acid. My problem is when I get the precipitate (impure benzoic acid) I have to ...
Ladybee's user avatar
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1 vote
1 answer
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What is a laboratory set-up for the synthesis of ethanol from ethene?

I am doing a chemistry investigation and one component of that requires me to synthesize ethanol from ethene. Ethene itself is gaseous at room temperature and pressure so I was wondering if someone ...
Abhijeet Vats's user avatar
7 votes
1 answer
219 views

What is the standard way of reporting/interpreting measurement uncertainty in scientific publications?

As an undergraduate student I was often told in lab classes to report every single measured or calculated quantity with its associated uncertainty in lab classes, in the form $(10.1 \pm 0.1 )~\mathrm{...
Ignacio's user avatar
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26 votes
4 answers
15k views

How are solvents chosen in organic reactions?

Just reading through organic chemistry book (Modern Projects in Organic Chemistry by Mohrig, et al.), and it seems like the choice of solvent is usually arbitrary. One of the experiments designed ...
Ryan David Ward's user avatar
1 vote
0 answers
533 views

How does toluene favor ortho/para in terms of kinetic and thermodynamic control?

If nitration of toluene is carried out at a very low temperature, presumably the reaction would be carried out under kinetic control. During these conditions that favor kinetic products, is more ortho ...
Ryan David Ward's user avatar
4 votes
1 answer
2k views

Are there any common and identifiable hazards to being a Chemistry Teacher? [closed]

I'm a High School Chemistry teacher. I have only been teaching for a few years and know very few other chemistry teachers. Of the ones I do, One has died of cancer, one is a cancer survivor and one is ...
L. Johnson's user avatar
7 votes
3 answers
38k views

What's the difference between pipettes calibrated "TD", "TC", "Blow-out" and related terms?

I've never blown-out the last drop of any glass pipette I've ever used during my undergraduate studies. Recently I re-read some notes I had lying around in order to prepare a class I had to give to a ...
Ignacio's user avatar
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7 votes
1 answer
9k views

Concentration of NaOH to dissolve glass

I am doing a physics experiment in which it is required to etch the outermost glass layer from a coverslip (regular lab apparatus). What concentration of NaOH should be dissolved in water, and how ...
Harshfi6's user avatar
  • 183
6 votes
4 answers
3k views

Is sulfide ion a stronger base than hydroxide ion?

I received these three responses. They are all, except the last response, incorrect to varying degrees. I am, however, unsure about how to grade these responses because the question itself, in my ...
Dissenter's user avatar
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8 votes
1 answer
305 views

What's the reaction here?

I have found a gif photo on the internet and I am very curious what is happening there? What reaction is the reason for that?
Numerical Person's user avatar
0 votes
2 answers
156 views

Calcium chloride hexahydrate has separated in jar - is it beyond saving?

I work in a lab where I'm in charge of ordering new supplies. A graduate student brought up a $500~\mathrm{g}$ amber jar of $\ce{CaCl2.6H2O}$ and pointed out that it had separated into a clear liquid (...
Joshua Bradley's user avatar
0 votes
3 answers
1k views

Does there exist a molecule of formule XαYβ where X and Y are elements that are also found in molecule XγYδ? [closed]

I am not a chemist, but I will be explaining chemistry to some third-graders. I want to give the example of how different things can be made of the same parts, but arranged differently. My "real ...
dotancohen's user avatar
1 vote
0 answers
54 views

Is there a generic graphical language to represent chemical reactions?

I want to show a schematic representation of chemical reactions from start to finish in a way that will include more detailed preparation instructions than a plain chemical formula: volumes, ...
Sparkler's user avatar
  • 4,257
8 votes
3 answers
3k views

Why does zinc plate copper in silver penny lab

In class, we performed a lab that involved heating a solution of zinc sulfate with zinc strips at the bottom of the beaker. A penny was placed on top of the zinc strips and soon after the penny became ...
Markovian8261's user avatar
5 votes
3 answers
6k views

Lab safety - Long vs. Short Sleeves on Lab Coats

I have three lab coats, two with long sleeves, and one with short sleeves. I saw that the concepts about lab safety vary from country to country; in some places it looks like the short-sleeve coat ...
jacksonbenete's user avatar
25 votes
1 answer
2k views

How can an inexperienced chemist determine the chemical structure of a molecule?

I'm a fairly inexperienced, but nonetheless interested chemist, currently planning a small project for the coming summer: I want to isolate an unknown chemical from a plant and determine it's chemical ...
user avatar
0 votes
1 answer
7k views

Why might the O—H stretch in the IR of MY triphenylmethanol product be less intense than expected?

Why might the O—H stretch in the IR of MY triphenylmethanol product be less intense than expected when compared to the expected IR for triphenylmethanol? I'm interpreting the IR I took of my product, ...
Marnius Rowling's user avatar
6 votes
1 answer
3k views

Possible Synthesis of MVK from 2-Butanone?

My professor wanted me to set up a lab to synthesize Methyl Vinyl Ketone (AKA Butenone) from some MEK we have lying around (2-Butanone). Now, I know there are multiple ways to do this, but the tricky ...
user97462's user avatar
9 votes
4 answers
1k views

How much does the quality of glassware matter, really?

Discussing about the pros and cons of glassware from different manufacturers for chemistry experiments easily becomes a heated debate. Well, that's how it seems if you read the chemistry related blogs,...
per's user avatar
  • 91
12 votes
2 answers
3k views

In which country is it allowed to practice non-clandestine amateur chemistry? [closed]

I travel a bit so am flexible where I live, and have taken a recent interest in chemistry to try to gain an understanding of physical reality. I find learning from textbooks to be good, but want to ...
user4779's user avatar
  • 691
3 votes
1 answer
2k views

Creation and Combustion of Nitrocellulose

I am intending to demonstrate the formation and combustion of nitrocellulose with my high school students, however I am concerned about the potential products of the combustion equation. I have been ...
Brett Harris's user avatar
2 votes
1 answer
2k views

How to make 0.3% ammonia water from 28-30% ammonia hydroxide

Can someone tell me how to make 0.3% ammonia water from 28-30% Ammonia hydroxide? I am trying to make a gallon or 3.78 Liters.
Jennifer's user avatar
1 vote
1 answer
341 views

Why isn't hybridization done in America? [closed]

Warning: This is a question from my teacher. In America hybridization isn't done, while in Europe it is done around the 10th grade. Is there any reason or advantage for doing(not doing) it as part of ...
MikhailTal's user avatar
6 votes
1 answer
4k views

How to interpret the instruction of the dilution of hydrogen peroxide?

I am required to prepare $\pu{120cm3}$ of hydrogen peroxide to each of one of my students tomorrow. Some material is given to me on the method of preparing the solutions. Within the method of ...
abdelmoniem's user avatar
9 votes
4 answers
12k views

Safe explosion demonstrations

As an end of high school treat, my class is trying to convince our chemistry teacher to make an explosion as a demonstration. What sort of reactions are beautifully explosive but safe enough to do in ...
CorruptedByMythbusters's user avatar
3 votes
1 answer
8k views

Distillation: Simple vs Fractional

Here is the excerpt of my lab manual: "Simple distillation is more useful for purifying a liquid that contains either a non-volatile impurity or small amounts of higher or lower boiling impurities. ...
yolo123's user avatar
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