# All Questions

28,671 questions
145 views

### How does Le Chatelier's principle apply to a gas phase reaction at constant volume?

This reaction is given in my book and the direction of shift of reaction on addition of $\ce{CO}$ and removal of $\ce{CO2}$ at constant volume is asked. $$\ce{2CO(g) + O2(g) ⇌ 2CO2(g) + \Delta H}$$ If ...
29 views

### Is it more precise to measure a substance as a solid or as a liquid?

If I have a substance and want to obtain an exact quantity of it, is it better to measure it as a solid or as a liquid? In other words, if I have, for example, NaCl crystals I can weigh the crystals ...
44 views

### Calculate Gibbs energy of dinitrogen pentoxide using its vapor pressure and sublimation

I am having trouble with the following problem: Dinitrogen pentoxide, $\ce{N2O5}$, is a solid with a high vapor pressure. Its vapor pressure at $\pu{7.5 °C}$ is $\pu{100 mmHg}$, and the solid ...
3 views

### Why does monoammonium phosphate (MAP) have 52% of phosphorus (P2O5)?

The formula of monoammonium phosphate (MAP) is $NH_4H_2PO_4$. Manufacturers say that MAP has 10% of nitrogen (N) and 52% of phosphorus (P). However, its molecular mass is 115 u and the atomic mass of ...
64 views

### Possible erratum in solutions to Orbital Interactions in Chemistry 2ed [on hold]

I was attempting the problems in Chapter 1 of Orbital Interactions in Chemistry, and found a slight problem. ftp://ftp.wiley.com/public/sci_tech_med/orbital_interactions_2e/Chapter%201%20-%20Answers....
512 views

### Inorganic chemistry handbook with reaction lists

There is a handy handbook on common inorganic substances' properties called "Reactivity of Inorganic Substances" (eds. R. A. Lidin, V. A. Molochko, and L. L. Andreeva). It was originally written in ...
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### Mass-Charge balance equations

How to write mass balance equations and charge balance equations of the solution composed of $\pu{0.1M}\text{ }\ce{ NaH2PO4}~ \text{and}~\pu{0.05M}\text{ }\ce{ Na2HPO4}$? After writing the equilibria ...
4 views

### Where can I look for a short chain photopolymer?

I am by no means an expert in this field, so please be patient with my explanation. I am looking for a photopolymer with very specific properties. I am not sure how realistic it is to find such a ...
34 views

### Definition of conjugation and Dewar resonance energy [on hold]

What is a precise definition of conjugation in organic molecules? Why, for instance, do we say a molecule like 1,3-butadiene is conjugated? A valence bond picture might argue the opposite, since ...
27 views

### MacGyvering medieval poison

Anyone know of any compound/substance one could have access to in a stone prison cell (From food? The rocks? The metal bars?) that could be processed through rudimentary means into a quick acting ...
17 views

### Buffer Systems, K(NH2)2 and HCL [on hold]

25 .00ml of 0.100M R(NH2)2 with $Kb1=1*10^{-4}; Kb2 = 1*10^{-7}$ is mixed with amounts of .100M HCL a.) 0 ml b.) 5ml c.)10ml d.)12.5ml e.)25.00ml f.)37.50ml g.)50.00ml h.)60.00ml What is ...
19 views

### What is the platinum doing in a Zippo hand warmer?

My Zippo hand warmer requires lighter fluid, platinum catalytic burner, and a heat source to start the flameless catalytic process. What is the platinum doing in this reaction?
21 views

### Confusion with molarity calculations

I am asked to calculate the molarity of TNB and BSA in assay and got a bit confused with the numbers. I know that the assay volume is 3ml and concentration of DTNB is 5ooµM, concentration of BSA is ...
20 views

### What is the reason for more stable keto form to tautomerise to a less stable enol form?

In the mechanism of SeO2 I have seen that a more stable keto form first converts to a less stable enol form and then yields a diketone. I have seen many other reaction where the reactant converts to ...
22 views

### Thermal Decomposition of nitrates [on hold]

I would like to see a visualisation of the thermal decomposition of nitrates. Something similar to this, from that I can understand a metal oxide and carbon dioxide would be formed, but for nitrates: ...
26 views

### Why aren't all double bond lengths equal in cyclobutadiene? [on hold]

even when there is a possibility of conjugation why aren't bond lengths equal?
13 views

### How does chelation control result in rate acceleration?

In the chapter on diastereoselectivity in Clayden, Warren & Greeves (2012), the Cram-Chelate model is discussed. Most significantly, under chelation control, the diastereoselectivity of the ...
15 views

### Conflicting info on TRIS buffer - pH6.8

I was about to prepare buffer for milk enzyme and to follow prep method described on bio-rad. But then I became suspicious and came across tons of information that pH6.8 is not in effective pH range ...
22 views

### How to take a sample of a hot salt solution without it precipitating in the cooler glassware due to the difference in solubilities at different temps?

I'm doing an investigation to see the effect of temperature on the solubility product of strontium hydroxide. I made a supersaturated solution left in the oven overnight at 85°C for equilibrium to be ...
19 views

### Parent and molecular geometry [on hold]

is the molecular geometry for carbon in formic acid trigonal planar. Also is the parent geometry for carbon in formic acid trigonal planar as well. Whilst the molecular geometry for hydroxyl oxygen in ...
707 views

### Identify KNO3 and KH2PO4 at home

I am not expert in chemistry. I need to find a way to identify a $\ce{KNO3}$ and $\ce{KH2PO4}$ powder at home. I suspect the seller gave me the wrong powder. What is a simple way to test between these ...
908 views

### Is it possible to speed up radioactive decay?

I’m aware that elements like $\ce{^14C}$ have a known half-life, which means that over a span of roughly $5730$ years, half of the $\ce{^14C}$ atoms decay into $\ce{^14N}$. Are there any substances ...
32 views

### Oxidation of diols using periodic acid

What are the orders of rates of oxidation with $\ce{HIO4}$ of the following diols? Explain with reasons. (a) $\ce{Me2C(OH)C(OH)Me2}$ (b) $\ce{Me2C(OH)CH(OH)Me}$ (c) $\ce{CH2(OH)CH2(OH)}$ (d)...
36 views

### HCl rota-vibrational lab: ab initio simulation of rotation constants

I'm trying to set up the simulation portion of the classic undergraduate lab studying the rotavibrational spectrum of HCl and DCl. In terms of simulation (using Gaussian 16), the equilibrium ...
19 views

### How do amphoteric compounds act as acids?

According to my chemistry textbook, an acid is a compound that gives hydronium ion on dissolving in water but amphoteric compounds like ZnO do not yeild hydronium ion on dissolving in water . I ...
16 views

### How to determine the number of water ligands attached to Pd in palladium chloride aquacomplex PdClₓ · yH₂O?

Normally this can be achieved using UV-vis: there is a strong absorbance around wavelength 220 nm which varies based on the number of ligands. If the palladium concentration is too high, the solution ...
27 views

### important Stoichiometry question, just need formula or help and answer checking [on hold]

How many grams of Cobalt(II) chloride CoCl2 is needed to make 0.645 liters with a concentration of 1.25 Molarity and the moles are .724? (the molar mass is 129.839 I believe)
12k views

### DL vs dl notation [closed]

As the L-isomer of glucose, it is the enantiomer of the more common D-glucose. Source: Wikipedia As far as I know enantiomers or Optical isomers are non superimposable mirror image structures with ...
4k views

### Why is arsenous acid denoted H3AsO3?

Inspired by this question, I'm wondering why arsenous acid is frequently denoted $\ce{H3AsO3}$, as opposed to $\ce{As(OH)3}$, which would appear to more accurately reflect its connectivity?  I ...
2k views

### The coldest (the most endothermic) reaction [closed]

What chemicals can you mix that causes the coldest (the most endothermic) reaction on a $\pu{kJ /kg}$ basis?
18 views

### The pH scale/calculating pH level [on hold]

How much water do you need to add to 10 mL of a solution of HCl with a pH of 4 to change the pH to 5?
13 views

### Calculating 'Air Dilution' Concentration to Estimate Final Odor Intensity [on hold]

Air flows at a rate of 1 l/min into a closed 40ml flask containing 2ml of amyl acetate serially diluted to 0.000002143% v/v concentration. The air-gas mixture then has the opportunity to escape trough ...
29 views

### Effect of solid in equilibrium

CaCO3 (s) = CaO (s) + CO2 (g) We know that pure solids quantity doesn't affect the position of equilibrium. But the application of pressure in gas does. If we add CaCO3 in the closed system, the ...
750 views

### What is the chemistry behind black colour of platinum black? [closed]

Platinum is a silvery white metal and is highly unreactive then why it's powdered form "platinum black" is platinum metal but is black in colour. why would a metal such as platinum become black as a ...
This question comes specifically from an IB Chemistry HL Paper 1 in May 2018 TZ1, namely question 8. Which complex has the greatest d orbital splitting? It gives 4 Complexes $\ce{[Fe(H_2O)_6]^{2+}}$,...