# All Questions

29,049 questions
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### Understanding Photo-chemical reaction variables in a photo-reactor

We are designing a lab that is based on photochemical reactions, but we have not learned about photochemical reactions in class, so I just wanted to get a better understanding of photochemical ...
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### Free induction decay in NMR (as stated in Pavia)

There is a statement in a very popular textbook of spectroscopy by Pavia (Chapter 3, Intro. to Spectroscopy), it says "The observed FID is actually an interference signal between the radiofrequency ...
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### Is acetanilide more soluble in water than diethyl ether?

Would acetanilide be more soluble in water at 25 degrees Celsius because it has an N-H and an oxygen that can participate in hydrogen bonding whereas diethyl ether only has an oxygen?
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### Software for conformational search [on hold]

I need a free software to perform a conformational search on molecules with 10 to 16 rotational bonds. What software would you recommend me? Where can I download it? Where can I find a manual of this ...
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### Which of the following ion will form most water soluble hydroxide? (A) K+ (B) Ni2+ (B) Zn2+ (C) Al3+ [on hold]

Which of the following ion will form most water soluble hydroxide? (A) K+ (B) Ni2+ (B) Zn2+ (C) Al3+
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### Why does anisole not hydrolyze in water solvent at low temperatures?

As per what i learnt about ethers hydrolysis, the oxygen protonates itself first and then the water and then water being a weak nucleophile, we first prefer the ether to cleave from either side to ...
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### What methods are used to detect a particular molecule? [on hold]

What methods are used to detect a particular molecule? I know of raman spectroscopy and "test" reactions (forming coordination complexes, iodine starch test, silver mirror test etc.)
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### Thickening and/or slowing evaporation of IPA-based ink

The conundrum I have a security printing ink that I make by adding an IR-absorbing dye to a 50/50 mix of Isopropyl Alcohol and distilled water. The ink solution is pale green but dries virtually ...
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### How do I identify the compound(s) that formed from a failed synthesis of another compound?

A general answer to the question is great, but specified to my problem is very much welcomed. My team had a lab project — to synthesize chrome alum crystals. We first dissolved $0.3 \, \rm g$ of ...
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### Would two different Plaster of Paris samples have different chemical signatures?

Weird question, but... would a spectroscopic analysis of a plaster of Paris sample reveal a chemical identifier that could be used to compare that sample against another. I want to be able to say ...
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### Find average rate of the reaction based on decrease of reactant's concentration

A reaction happens where $\ce{A}$ is converted into $\ce{B}$. It takes $\pu{4 min}$ for the concentration of reactant $\ce{A}$ to decrease from $\pu{3.0 M}$ to $\pu{1.0 M}$. What is the average rate ...
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### Determing wheter a particle is stable with respect to strong and electromagnetic reactions [on hold]

Given the decay $Λ_b(5620) → K^− + P_c(4380)+ → K^− + J/ψ + p$ I was asked as a homework question , to consider all hadrons containing b quarks, to determine whether $Λ_b(5620)$ is stable with ...
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### Why is the graph of fluorescence vs. wavelength continuous?

If the emission of a photon from an excited state to the ground state occurs with a precise energy, then why is it that wavelengths that differ from lambda max have values on a fluorescence vs. ...
A gas described by van der Waals equation has the pressure that is lower than the pressure exerted by the same gas behaving ideally. True or false? My approach $$P(\text{ideal}) = P(\text{real}) + P(... 0answers 25 views ### Using Delta G to find melting/boiling points of compounds? Help [on hold] So I decided to have some fun using the concept of Delta G to see if i can calculate melting points and boiling points for compounds. I was looking at the following reaction: NaOH(S) --> NaOH(l) I ... 0answers 13 views ### Butan-2-ol to Butanone using only H2SO4 as oxidising agent Is it possible to oxidise the alcohol in question with just concentrated H2SO4 (without the need for a Chromic substance) and if so what does this mechanism look like? 2answers 48 views ### The equivalent weight of HNO3 in the following reaction [on hold] The equivalent weight of HNO3 in the following reaction is ‘x’, then the value of x/21 is 3Cu+8HNO3⟶3Cu(NO3)2+2NO+4H2O in this I atempted by using redox formulas but my answer is comming 1 but ... 0answers 15 views ### Friedel Crafts Acylation: Reaction of acyl halide with catalyst To form an electrophile for this reaction to occur, the acyl halide interacts with the catalyst. However, on reviewing the conditions for the reaction, I have encountered that the 2 equivalence of the ... 0answers 7 views ### Rate of nucleophilic addition reaction of carbonyl compounds How should I compare the order of rate of 1.formaldehyde 2.ethanal 3.p-nitrobenzaldehyde 4.p-methoxybenzaldehyde For nucleophilic addition the rate depends on the intensity of electron deficiency of ... 1answer 45 views ### Why is casein hydrophobic? According to this source hydrophobic behaviour occurs when a molecule does not have a charge or is neutral and therefore cannot be attracted to the negative nor positive parts of water. Casein has an ... 1answer 32 views ### Derive expression for heat flow from oil bath to metal sphere A spherical ball of iron is put into a hot bath of oil. The iron ball is initially at a low temperature and heat transfer from the oil to the iron will increase the temperature of the iron ball. ... 0answers 16 views ### Concentration Conversions [on hold] I did an experiment trying to calculate how much energy was used to evaporate water with different ammounts of NaCl. In the experiment, I put 71g of NaCl then filled the beaker with water to the ... 1answer 33 views ### Why does color change during chemical reactions? [on hold] I asked this question somewhere and I got the answer as the the very fundamental arrangement molecules changes which leads to different optical properties of the substances. I can't express the ... 0answers 9 views ### Do fabrics assimilate airborne dioxins? [on hold] Do natural or synthetic fabrics (clothing, etc) dissolve/trap dioxins and dioxin-like compounds from third-party/external sources such as airborne plastic fumes or soot? Also, is it safe to assume ... 1answer 23 views ### pH of a Calcium Hydroxide vs Magnesium Hydroxide solution [on hold] In an AQA 2017 Chemistry paper, a 0.0131 \pu{mol}\cdot\pu{dm^-3} saturated solution of calcium hydroxide is prepared and then the question asks to predict the pH of a similar solution of magnesium ... 0answers 15 views ### Amount of moles [on hold] Using the molarity of sodium hydroxide (0.50M) and the volume of sodium hydroxide used to find the equivalence point (13.5mL), determine the moles of sodium hydroxide used. 0answers 16 views ### Can dioxins be absorbed through the skin? [on hold] I am aware that excessive/long-term exposure to dioxins dioxin-like compounds can cause skin problems (chloroacne) and their great affinity to lipids/fats, but I was wondering if the same occurs at ... 0answers 35 views ### how to count total number of stereo isomers? please see the question below(i don't know how to approach question my teacher just told me to use the formula 2^n where n are number of chiral carbons but it doesn't work always please can some one ... 1answer 23 views ### Solubility of Iodine in different solvents The solubilities of iodine in \ce{CCl4,n-Hex,Et2O,PhCH3} were given respectively as 19 g/kg, 13 g/kg, 337 g/kg, and 182 g/kg. These results puzzle me for the following reasons: 1) Iodine, being a ... 0answers 19 views ### Order of acid-carbonate reactions [on hold] For an assignment I am investigating the reaction$$\ce{MCO3 + 2HCl -> H2O + CO2 + MCl2} where M is a group 2 metal and zinc. I am investigating changes in the rate of reaction and for that I ...
Calculate $\mathrm{ pH }$ of $\pu{ 0.05 mol }$ of $\ce{Zn(CH3COO)2}$ and $\pu{ 0.025 mol }$ of $\ce{ NaOH }$ dissolved in $\pu{ 1 L }$ of distilled water? I tried to use the systematic method by ...