# All Questions

28,634 questions
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### Why are synthetic pH indicators used over natural indicators?

Synthetic indicators seem to be exclusively used when determining the pH of a substance with an indicator (with the exception of that school experiment where you boil cabbage to demonstrate natural pH ...
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### Is there a name for this algorithm to calculate the concentration of a mixture of two solutions containing the same solute?

There is an algorithm called "Mischungskreuz" (German for "x of mixing") that is sometimes taught as a shortcut to figure out the following problem: You have two solutions that contain a solute at ...
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### How do I make 100 milliliters of 100mM H2O2 using 3% H2O2?

I need to make 100 milliliters of 100mM H2O2 using 3% H2O2. Do I: add X milliliters of distilled water to the 3% H2O2? How many ml? or add X milliliters of 3% H2O2 to the distilled water? How ...
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### Is there a error at page 566 of Atkins Physical Chemistry?

At page 556 I found this question being analyzed and the rate law is provided. However, when I apply steady state approximation, I can't find the result without the coefficient 2. Is it me being ...
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### What factors affect energy density?

I know that intermolecular force strength as well as steric effects (entanglement) are factors that affect energy density. Someone suggested the exclusion effect to be another, though I don't ...
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### Using Roman Numerals to indicate a compound

I don't completely understand it's use. Here's an example I don't understand: Shortly after discussing $\ce{[CuCl4]^2-}$, an exam paper asked a question about copper(II) chloride. I understand that ...
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### solution 3 results from combining solution 1 with soultion 2. Just need a formula or equation [on hold]

solution 3 results from combining solution 1 with soultion 2. solution 1 consists of 2ml of cells at a concentration of 5x10^6cells/ml. solution 2 consists of 7.0ml of cells concentrated at 3x10^6 ...
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### How to make auto zero in calibration graph during graph plotting?

I am using Origin 9.1 software for graph plotting. I have collected data from Ion Chromatography Instrument. Peak area vs conc. It should be y = mx type of graph Fitted graph shows in few cases ...
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### In Ion Chromatography instrument, Does the specific conductivity (peak area) of an analyte depends upon background conductivity?

In Ion Chromatography instrument, Does the specific conductivity (peak area) of an analyte depends upon background conductivity ? Assume Specific Conductivity (peak area) of fluoride ion is 4 unit ...
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### A hydrated transition metal ion is colourless. Which of the following could be the electronic configuration of this ion?

Here are the options: A [Ar] 3d$^{5}$ 4s$^{2}$ B [Ar] 3d$^{8}$ C [Ar] 3d$^{10}$ 4s$^{2}$ D [Ar] 3d$^{10}$ I would have thought B, as it has an incomplete d-subshell, and it doesn't have any 4s ...
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### a 100 ul stock solution of DNA is at 167 ug/ml. to what volume should you dilute the stock to achieve a working concentration of 40ng/ul [on hold]

a 100 ul stock solution of DNA is at 167 ug/ml. to what volume should you dilute the stock to achieve a working concentration of 40ng/ul
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### Why NCl3 and PCl3 gives different product on hydrolysis? [duplicate]

My answer: N and Cl form non polar bond due to similar electronegativity. N doesn't have empty d orbital so hydrolysis takes place with donation of lone pair of N to H-atom of water. PCl3 forms polar ...
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### How to recreate bioluminescence in fireflies in a lab?

I have several mg/mL of D-luciferin, luciferase (firefly), ATP solution (25 mmol) and MgSO4 (for the mg2+ ions). The experiment has to be done in cuvettes of 2,5 mL (if I get any results, it will be ...
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### Why copper has special electronic configuration [on hold]

Cu configuration is different. How can chemists decided its configuration.
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### Which of the 2 structures is more stable?

As far as I know, alkenes with more number of hyperconjugating structures are more stable. Hyperconjugation has a greater stablizing effect than Inductive effect. So, (d) should be more stable as it ...
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### Effect of temperature on concentration of ammonia in trichloromethane

By reviewing some literature on the distribution of ammonia in water and trichloromethane, I've found that increasing temperature decreases the partition coefficient of ammonia given that the formula ...
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### Why there is a need of independent definitions for both mass and mole?

Considering that the two quantities are linked by reality, how can be both imposed by independent definitions? I am aware that the change taking place next May does not effect common weighing in ...
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### Does iron nail sink in rubbing alcohol [on hold]

I have been trying for so long to get answer
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### Melting point of aspirin, contradicting sources

Querying wolfram alpha for the melting point of aspirin (link) returns $\pu{140 °C}$. The Wikipedia page for Aspirin lists $\pu{136 °C}$ instead, citing this book. How am I supposed to know which ...
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### What methods could be used for determining the concentration of Zn2+ in a solution?

I know that complexometric titration with EDTA is one method. What other methods could be used?
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### If magnesium reacts with oxygen to produce magnesium oxide only on the application of heat, then why isn't it categorised as an endothermic reaction?

Why isn't the energy that is used to overcome the activation energy of magnesium metal atoms to react with oxygen, not taken into account?
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### Solids to liquids process

Melting point is the critical point at which a solid starts to be transformed into a liquid? Does this mean that the geometric lattice of a solid is broken?
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### I conducted some experiment and I want to know the resulting redish black thing

I placed two electrodes in a jar and poured the sparking water with lemon flavor. After about 5 hours, the water turned to blue and the negative probe had the redish black thing. I'd like to know what ...
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### Which diatomic molecule would have the largest bond energy? [on hold]

Of the following diatomic molecules is I2 the molecule with the largest bond energy? F2 Cl2 Br2 I2
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### Is it stupid to put used acid into a pool after cleaning the chlorinator? [on hold]

I have a salt pool, and when the chlorinator salts up with calcium, I clean it with a diluted acidic solution. What happens to the acidic solution after the reaction happens? I.e., does the pH change?...
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### Does the Location of Line-Dash-Wedge Notations Matter?

In Line-Dash-Wedge notation, when illustrating that an atom or bond is directed towards or away from the viewer (solid triangle for coming forward, dotted lines for going back), does the location of ...
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### Reimer–Tiemann reaction of 2-naphthol

What are products obtained when 2-naphthol or β-naphthol is subjected to Reimer–Tiemann reaction? I am confused whether formylation will take place at the 1st position or 3rd position with respect to ...
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### How to describe the enthalpy of acid dissociation in aqueous solutions?

How to describe the enthalpy of acid dissociation in aqueous solutions? If we had a weak acid "PB" that dissociates to give a proton and a conjugate base. Classically it would be described like the ...
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### Natural deodorant with magnesium powder turning neon yellow! [on hold]

I am not a chemist but need some help. I make organic deodorant with magnesium instead of baking soda for folks with sensitive skin. But the deodorant often turns bright, neon yellow when it gets ...
628 views

### What exact color does ozone gas have?

This answer to a now closed question says that ozone gas has a "slight blue" color. But there are lots of blue colors: sky blue, ultramarine, phthalo blue, many others — what is closer to the color of ...
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### Why does carbon steel remove garlic odor from fingers?

What reaction is responsible for the well-known ability of carbon steel implements (e.g. a chef's knife, or cleaver), being used to remove garlic odor from one's fingers after chopping/slicing it? ...
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### Iodoform on acetone gives one product?

During the Iodoform reaction of acetone why does the second iodine addition happen on the carbon that already has undergone substitution instead of the other carbon?
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### Haloalkanes and Haloarenes [on hold]

What are the product that we get on reaction of ethylene glycol with excess HI? Confused that both OH will go substitution or elimination then addition
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### Are the dsp3 hybrid orbitals degenerate? [duplicate]

I learned in general chemistry that hybridization of n orbitals produces n hybrid orbitals with the same energy (degenerate). However, in Housecroft and Sharpe inorganic chemistry, I read the ...
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### Which of the following sustituents has the highest priority according to sequence rule? [on hold]

A) - CH(OCH3)2 B) - COCH3 I aswered it b ,but my teacher says its a. I can't understand why !! I am sure it is b!! Please, explain for me.
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### Finding all Chemical Reactions Given Products and Reactants [on hold]

Given only the products and reactants, is it possible to find all possible chemical reactions involving those species? Consider e.g. the example that user Floatzel98 had in his original post before ...
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### Why is the H2O molecule an antigen despite its tiny size and simplicity?

I just saw a news article about a woman with Aquagenic Urticaria which basically means she produces antibodies against H2O molecules which causes very bad symptoms if she touches or drinks water. We'...
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### Copper powder amount dissoved in water [on hold]

How much copper powder dispersed into 2 liters of water will result in a 10 ppm concentration? I am not a chemist.
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### Ethers hydroysos in acidic medium [on hold]

Plz provide the detailed to how to hydrlyse this ester.
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### How to quickly diffuse a dye through still water

I'm doing an engineering experiment soon and would like to be able to quickly dye water. The water is still (i.e. not moving) and I would prefer not to physically disturb the water as best I can. ...
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### Why neglecting OH Ions from charge balance?

I have a problem, in which the concentration of $\ce{Ca^{2+}}$ ions in water should be related to the partial pressure of $\ce{CO2}$ (assuming the water is an open system and in equilibrium with ...
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### How to sythesize gamma-Aminobutyric acid [on hold]

I want to synthesise gamma-Aminobutyric acid (GABA) an amino acid. Can anyone point me towards some clear instructions? Regards,
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### What is the expected trend in the evaporation rate of a mixture of alcohol and essential oil considering both are volatile? [on hold]

A volatile solvent and volatile solute mixture. Can you guide me to some studies that have literature values or that justifies why and whether the evaporation rate of these mixtures will increase or ...
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### molecular orbital theory

i read in my textbook that the energy diagram of moleculal orbits is different for atoms nitrogen and below them. my question is which one of the energy diagrams to use in heteronuclear compounds like ...
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### Ionic equilibrium between multiple ions

This is a question from IIT-JEE 1993: For the reaction $$\ce{[Ag(CN)2]^- -> Ag^+ + 2CN^-}$$ the equilibrium constant at $\pu{298 K}$ is $\pu{4e-10}$. The silver ion concentration in a ...
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### Stoichiometry of the redox reaction with crystallohydrate

Consider the following balanced equation: $\ce{2 Al(s) + 3 CuCl2 . 2 H2O (aq) → 3 Cu (s) + 2 AlCl3 (aq) + 6 H2O (l)}$ If we began the experiment with 0.99 g of Al, according to the ...
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### Effect of spontaneous transmutation of atom in crystal

What happens to a compound when one of its atoms changes via spontaneous nuclear reaction to an atom with very different bonding? For example, suppose an atom of beryllium-7 in a crystal of $\ce{BeF2}$...
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### Can a stoichiometric mixture of oxygen and methane exist as a liquid at standard pressure and some (low) temperature?

This answer to the question Pre-mixing cryogenic fuels and using only one fuel tank written by a non-chemist (me) begins with: At STP: LOX's boiling point is 90.19 K Methane's freezing ...