Top new questions this week:
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I have calibrated pH sensors in the lab on several occasions and have used standards of 4.0, 7.0 and 10.0 usually. Recently I received a sensor and was tasked to calibrate it, but it requested …
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Why is collagen fibre autofluorescent? Proteins with increased amount of trp, tyr, phe tend to fluoresce but I don’t think collagen fibre has increased percentage of any of them. Some say collagen …
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I have bought a colour changing lipstick with the colour Phloxine B.(Other ingredients, see below…) Normally this colour changes to pink at pH 5. So this means on skin it changes its colour because …
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In this article (oceanexplorer.noaa.gov/explorations/16carolina/logs/sep3-2/sep3-2.html) and articles like this one, Styrofoam cups were taken to the depths of the ocean in an AUV to …
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I was wondering whether anyone has demonstrated that a liquid will have a higher boiling point if it is placed in a very large electric field. I believe to be the case, since induced dipoles would be …
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In the basic oxygen process, steel is made from pig iron (having a high carbon content) by oxidising the carbon with a high-pressure oxygen lance. In an EAF, steel is made mostly from scrap, but it …
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First off, I checked and there are indeed a number of questions on copper patinas, but none which deal with brittleness. Context I own a number of copper writing utensils, which I’d like to get a nice …
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Greatest hits from previous weeks:
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This is a 10th-grade question. The melting point of a substance decreases with increase in presence of impurities in it. The melting point of ice decreases from 0 °C to -22 °C on mixing salt in it …
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In mineralogy class, I was taught that metallic and ionic bonds are weaker than covalent bonds and that’s why quartz and diamond have such a high hardness value. However, in organic chemistry class, I …
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Nodes are the points in space around a nucleus where the probability of finding an electron is zero. However, I heard that there are two kinds of nodes, radial nodes and angular nodes. What are they …
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A mixture is made by combining 110 mL of 0.15 M $\ce{HCl}$ and 215 mL of 0.055 M $\ce{HI}$. What is the pH of the solution? $$\ce{HCl -> H+ + Cl-}$$ $$\ce{HI -> H+ + I-}$$ According to what I …
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I was reading about the p-block elements and found that the inert pair effect is mentioned everywhere in this topic. However, the book does not explain it very well. So, what is the inert pair effect? …
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What is the correct way to calculate the concentration $\ce{H3O+}$ in a solution with $\ce{pH}=6.99$? Attempt 1. pH<7, therefore there are only $\ce{H3O+}$ particles in the solution. $[\ce{H3O+…
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It is said that covalent bonds are directional, while ionic bonds are not. Why? Is it because of the orientation/directional properties of the overlapping orbitals?
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Can you answer these questions?
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When water is in vapour state, to which degree is there still some dissociation with the existence of charged species like $\ce{H3O+}$ and $\ce{HO-}$? (I would be interested by any reference to …
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So recently I was performing an esterification reaction of oils like peanut oil or any neutral oil where I got some products which are only possible to filter using fractional distillation. I already …
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I’m reading Unit operations of Chemical Engineering, 5th edition by Warren McCabe. They defined the “molar density $\rho_{M}$” as $\ce{\rho_{M}=\frac{n}{V}}$. The parameters $n$ and $V$ are …
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