Questions tagged [chemistry]

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30 views

What chemical can be used to restore synthetic rubber?

When rubber (I don't know the specifics, but I assume it's butyl rubber) gets old, it turns into one of two states usually: It becomes sticky and gummy. It becomes hard and brittle. I'd like to know ...
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1answer
14 views

What is the mechanism of adsorption-desorption on biochar obtained from slow pyrolysis/ torrefaction?

Biochar is a major by-product from pyrolysis along with bio-oil and it is considered an important chemical feed-stock because of many light oxygenates. I have read some papers on using bio-char use ...
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1answer
33 views

What's a good way to equalize pressure between 2 spaces without allowing gas exchange under normal circumstances?

I have a reaction chamber where gasses are injected to maintain a certain mixture. The container is sort of like a bell, where the bottom is submerged in water to make a seal. The issue I have is ...
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0answers
28 views

What is the smoke made by the fogging machine? Is it harmful to humans?

What is the principle of a fogging machine ? on what process a fogging machine depends ? distillation or vapourization ? what is the harmful effect of fogging machine ?
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2answers
40 views

Why does aluminum clad steel wire have high corrosion resistance?

Why do aluminum clad steel wires have high corrosion resistance despite being two dissimilar metals? Does the aluminum act as a protective & sacrificial layer similar to zinc in galvanization or ...
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1answer
52 views

pH calculations for boiler water

For water steam cycle in a "combined cycle power plant" containing 3 boiler drums and dosing of 5% ammonia solution in the condenser. How can I calculate the pH of the boiler water in each of the ...
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1answer
34 views

Generic category of PBT thermoplastic

I'm an EE, but I'm working on a project at work where I need to venture into materials science & chemistry. My question is, does thermoplastic, Polybutylene terephthalate (PBT), fall into any of ...
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1answer
60 views

Calculate the specific surface area of a mesoporous sample

I'm a nanoengineering student who's been stuck on the following problem for a few days. I've gone back over my professors slides, watched podcasts from an old professor, etc. etc., but don't ...
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0answers
18 views

Referencing for Air Quality Monitoring

I asked the same question in electronics sub, but since it is more general I am asking it here again. I bought the Sharp dust sensor GP2Y1010AU0F. Below are the graph of readings indoor for ~5 minutes,...
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2answers
72 views

How can I vaporize metals?

What are some common ways that I can vaporize Metals into a vacuum chamber? How can I keep these Metals in a gaseous state?
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0answers
22 views

How to quantify adulteration of urea and hydrogen per oxide in cow milk? [closed]

I am very much new in this field and trying to get some information on adulteration of cow milk. I have searched and saw that mostly urea and hydrogen per oxide are mixed with cow milk. I found that ...
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0answers
17 views

Safely evaporate electrolyte from fragile porous substrate

We have porous ceramic platelets of ~50x5x1 mm³ thickness infiltrated with ammonium nitrate solution (NH4NO3). We want to decompose and evaporate it w/o damaging the fragile substrate (decomposition ...
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0answers
87 views

Eletrolysis of water

The electrolyser used in the process at 25°C and 10.0 bar exhibits a global yield of 82% with a potential of 1.481 V. Determine the electrical energy that can be electrolyzed by year in order to get ...
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1answer
34 views

What does it mean by “loops and troughs”? [closed]

Actually, I've asked this question in "English Language & Usage" but someone told me ask it here! What does it mean by "loops and troughs" in: "Source has acquired a pattern of loops and troughs."...
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1answer
338 views

Mass balance of a recycle stream

I'm a chemical engineer student and I have just started to learn about mass balance without reaction. This is my problem - I want to find Out the mass composition and mass flowrate of stream Y (...
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1answer
736 views

Calculate the radius of iridium atom, given that Ir has an FFC crystal structure, a density of 22.4 g/cm3 and atomic weight of 192.2g/mol [closed]

Calculate the radius of iridium atom, given that Ir has an FFC crystal structure, a density of $22.4\text{g/cm}^3$. and atomic weight of $192.2\text{g/mol}$. Everyone whom I asked this question ...
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2answers
51 views

Energy balance for a system

A hydropower plant uses a river to generate electrical energy. It has a drop of $107m$ and the flow rate of water is $275$ $m^3$/$s$. The flow rate of the water is the same in and out of the system. ...
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1answer
126 views

Are brass and copper utensils safe for humans to eat from? [closed]

In my research over the internet everyone is telling that brass is not safe but still there are solenoid valves, joints, and piping made of brass used in everything like coffee machines, water ...
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2answers
76 views

is it possible to achieve 1000C temperature in a cabin?

is it possible that if i have a cabin which is insulated from outside but is built with some sort of material like copper and there is a heating element of sort which is providing 100C constantly but ...
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2answers
77 views

Nylon brittleness as function of moisture content

Can someone explain the how/why Nylons brittleness is to some degree a function of it's moisture content. I don't understand HOW the water content changes the elongation at break of the material. ...
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2answers
54 views

Chemical engineering calculations - basis

You have a gas of the following compositions : 40% N2, 30% CO2, 30%,CH4 in a tank . What is the Average Molecular Weight of the gas if your compositions is based on molar ? I found that the AMR with ...
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0answers
45 views

Batteries for electric airplanes [closed]

I'm interested in the development of electric small airplanes with 4 or 6 seats, that could really happen in the following decades. One of the main problems related to this project would be the ...
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2answers
608 views

Epoxy curing, heat or no heat?

Most if not all of the off-the-shelf epoxies I've used have generated a fair amount of heat while they are hardening. This seems to indicate to me that these are exothermic reaction, i.e. they ...