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519 views

Is this reaction to produce ammonium sulfide safe?

For my chemistry experiment, I was assigned to produce ammonium sulfide and test the chemical properties of the compound. From my online research, I found out that I can mix household ammonia and ...
1
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1answer
244 views

the perfect campfire

As far as chemistry goes, there are laws or observations that can be useful to determine the perfect shape and disposition of the wood in a campfire ? For example what chemistry says about the 2 most ...
1
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3answers
17k views

C + O2 is equal to C + O, how is that possible

C + O = CO2 . This is because carbon has valency of 4 while oxygen has valency of 2. When they react the valencies are criss crossed which means we will get C2O4 but this is simplified to CO2. But ...
13
votes
3answers
6k views

Correlation between Coulomb's law and VSEPR theory

I've always been told in chemistry lessons that lone pairs repel more due to a greater charge density than bonding pairs. And that makes sense when steric effects are involved when bond orbitals ...
2
votes
1answer
225 views

Ratio of conjugate bases of a tricarboxylic acid

Hi does anyone know how to solve this question? A tricarboxylic acid $\ce{H3A}$ has three different types of $\text{p}K_\text{a}$ $(\text{p}K_\text{a, 1} =2.0,$ $\text{p}K_\text{a, 2}=5.0,$ $\text{...
1
vote
1answer
492 views

Predict the product (organic chemistry) [closed]

I think that the first reaction would add into the ketone carbon, but I don't know where to go after that. A step-by-step explanation of the answer would be greatly appreciated! Answer choices:
2
votes
2answers
424 views

What is this wave function in Chemical bonding?

Was studying chemical bonding(Valence bond theory) but there came this topic called wave equation but have not studied quantum mechanics,so finding hard to understand these terms.Please help!!!
4
votes
1answer
765 views

Deriving goldman equation

So I've been trying to follow the derivation of the Goldman-Hodgkin-Katz equation on Wikipedia (https://en.wikipedia.org/w/index.php?title=Goldman_equation ) - I can follow it through after it sets up ...
6
votes
3answers
40k views

How to rationalise that when we dilute a weak acid, the pH increases but also the dissociation increases?

When water is added to a weak acid like ethanoic acid, the number of ethanoic acid molecules that dissociate increases, however, pH increases (less acidic), too. Why is this so?
0
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3answers
1k views

Which temperature is meant in the Gibbs free energy equation? [closed]

In the equation for Gibbs free energy change, $\Delta G = \Delta H - T\Delta S$, does $T$ refer to the temperature of the system or the surroundings? I know we have to calculate Gibbs free energy of ...
3
votes
3answers
24k views

Boiling point of a liquid increasing with temperature?

In my textbook, a statement is given, as follows: Boiling point of a liquid increases with increase in temperature However, I was wondering, isn't this wrong? The boiling point of a liquid always ...
4
votes
2answers
3k views

Which branches of chemistry and in what order to learn (self study)?

Hi I have decided to give chemistry another shot (it didn't take so well way back in high school). My main interest is for reading up on brain chemistry and pharmacology. I currently have a textbook ...
1
vote
0answers
124 views

Discrepancy in current inside an electrolytic cell

Suppose A(+)B(-) type fused salt is present in an electrolytic cell (not electrochemical cell). Let n electrons be entering the cell per second. Since each A(+) requires one electron to discharge, so ...
6
votes
3answers
340 views

Aldol of 7-oxooctanal

I want to do intramolecular aldol condensation of 7-oxooctanal: I am talking about the major product. Clearly, a 6-membered ring would be a major product, but there are 2 possibilities: taking ...
13
votes
1answer
2k views

Stability of cyclobutyl methyl carbocation

I know that cyclopropyl methyl carbocation is exceptionally stable compared to say, benzyl carbocation. But I want to know how stable is cyclobutyl methyl carbocation compared to say, tertiary/...
-1
votes
1answer
4k views

What is the product of CO + 2H2 under normal pressure?

Under the pressure of $\pu{340 atm}$ $$\ce{CO + 2H2 <=> CH3OH}$$ But what is its product during normal pressure of $\pu{1 atm}$? I think it would be a single displacement reaction $$\ce{CO +...
3
votes
1answer
322 views

A reversible exothermic reaction between a molecule in an excited triplet state and a reducing agent

Say I promote a molecule to a triplet state via repeated electronic excitation events. Here, this is going to mean that an electron from the HOMO level, originally with a spin-UP and spin-DOWN ...
2
votes
1answer
12k views

Why is it OH- and not HO-? [duplicate]

I am told that in a chemical equation the metal comes first and then the non metal. for example MgO, ZnSO4,etc. But when both the elements are non metals or metals, the one with the lower atomic ...
2
votes
3answers
17k views

Why does Pb normally have an oxidation number of +2?

Why does $\ce{Pb}$ have an oxidation number of $2^{+}$ while carbon and other elements in the same group have an oxidation number of $4^{+}$? Furthermore, why doesn't carbon also have a $2^{+}$ ...
2
votes
1answer
29k views

Why does NaCl dissolve in H2O despite its strong ionic bond? [duplicate]

If $\ce{NaCl}$ is such a strongly bonded ionic compound, why it does it disassociate so readily in $\ce{H2O}$? One would think that because of the very strong ionic bond it would not disassociate it ...
1
vote
2answers
13k views

What reaction takes place when potassium iodide is added to a tetraammine copper(II) complex?

I am given a blue solid W and it contains a tetraamine copper(II) complex and a $\ce{SO_4^{2-}}$. I added dilute sulfuric acid until the solution is pale blue; then added potassium iodide solution. A ...
16
votes
2answers
7k views

Are atoms really round?

I'm not sure if this is a silly question, but I was sitting here with a cup full of cheezey poof balls thinking, "My goodness, it's like an amazing cheesey delicious liquid - huge water molecules!" ...
0
votes
1answer
42 views

Spectrophotometry for Colourant

I have been looking for a paper that by using spectrophotometry method, we can determine rate of reaction of colourant. I could not find any paper. I was wondering if any body could help me.
5
votes
1answer
1k views

Correlation Diagram Doesn't Match Selection Rules?

From Miessler's Inorganic Chemistry, 5th edition, there is this correlation diagram for $d^{2}$ in a octahedral field. On the left hand side, if it's not clear, it goes (from lowest to highest): $^{...
0
votes
2answers
514 views

Best solvent for crystallization + mass recovered from crystallization + purity of the product

I have a chemistry final tomorrow and this question on my sample exam through me for a loop. I'm not entirely confident I can work out problems B and C, but those questions rely on the answer to A. ...
9
votes
3answers
45k views

CH4 + O2 => CO2 + 2H2, what's wrong with it?

It says in my textbook that: $$\ce{CH4 + 2 O2 -> CO2 + 2 H2O}$$ which seems like a displacement reaction to me. Shouldn't the reaction be: $$\ce{CH4 + O2 -> CO2 + 2 H2}$$ since $\ce{4H}$ ...
1
vote
2answers
1k views

Why is NH4OH used in Polarimetric analysis?

Why is a sugar solution pre-treated with ammonium hydroxide before analyzing? And why is it specifically ammonium hydroxide instead of sodium hydroxide or calcium hydroxide?
4
votes
1answer
11k views

Incomplete Combustion products

In class we performed an experiment which I am unable to understand the results for Why does the the amount of soot produced vary? What is the amount of soot produced dependent on? Experiment: ...
2
votes
1answer
823 views

Preference of grignard between aldehyde and double bond?

Quick question, in this reaction: 2-Butenal + CH3MgBr --> ?? Will the grignard attack the double-bond or the aldehyde carbon? Please explain this preference, thanks!
1
vote
1answer
920 views

Testing a sodium aluminate solution

I prepared some sodium aluminate by reacting a strong $NaOH$ solution with aluminium foil and filtering the result. I now have a clear solution and I'm not sure what it is. I stopped adding aluminium ...
2
votes
4answers
2k views

Role of heat in combustion

What role does heat play in the combustion process.Specifically, does the amount of heat determine whether complete or incomplete combustion occurs, and is the amount of heat impacted by the amount ...
0
votes
2answers
289 views

Figuring out the theoretical mass of reactants?

Hi Stackexchange Community, I'm working on my chemistry lab report. The initial instructions were to test the hypothesis that the mass of products of a reaction will equal the mass of the reactants. ...
1
vote
2answers
7k views

Determine which molecule has stronger intermolecular force?

SiH4 and CH4 The only intermolecular force they both have is London Dispersion forces Strength of LDF is determined by molar mass molar mass of SiH4 = 32.132 molar mass of CH4 = 48.42 Therefore ...
1
vote
1answer
764 views

Can an excessive reactant amount result in a longer reaction time?

I am performing an experiment with DTZA and Ferrate. After a point of increasing the DTZA concentration too much the Ferrate takes longer (lower reaction rate) to react with the DTZA. Is this ...
5
votes
2answers
1k views

Coconut aldehyde mechanism

How would you draw the mechanism going from non-3-enoic acid to coconut aldehyde (5-pentyloxolan-2-one)? I know I added sulfuric acid and sodium carbonate, which I was confused how they worked into ...
3
votes
1answer
259 views

Why can't the molecularity be determined from the rate law?

Basically can someone explain why the molecularity cannot be determined from the rate law?
17
votes
2answers
2k views

Why does free chlorine in the stratosphere lose its ozone-depleting potential after about 100,000 reactions?

Free chlorine ($\ce{Cl}$) in the stratosphere can deplete ozone ($\ce{O3}$) as follows: $$\ce{Cl + O3 -> ClO + O2}$$ The chlorine atoms can then react with oxygen and return to the beginning of ...
2
votes
1answer
318 views

Charge of polyatomic ions doesn't equal the charge of ions it consists of?

I'm taking entry level collage chem. class, and we got to this topic that I don't really understand. I think I understood what an ion is (a atom whose amount of electrons is not equal to amount of ...
29
votes
3answers
26k views

Why is the bond length of CO+ less than that of CO?

According to molecular orbital theory, the bond order of $\ce{CO}$ is 3. When $\ce{CO+}$ is formed, the bond order decreases to 2.5, and thus the bond length should increase. However, the bond length ...
1
vote
1answer
2k views

Does potassium aluminum sulfate have any effect on sexual performance/sperm counts or anything relating to the functionality of the sexual organs?

I recently read about potassium aluminum sulfate that it has astringent property and has the ability to constrict body tissues and restrict blood flow. Since, for penis, the erection happens with the ...
4
votes
1answer
592 views

Most common material in the universe

I was told that 'water' was the most common material in the universe and I disputed that claim. I was met with the argument that hydrogen and oxygen were the most common atoms in the world so water ...
8
votes
3answers
24k views

What is the difference between doxycycline HCl and doxycycline hyclate?

I would like to ask what are the main differences between doxycycline HCl and hyclate? I work in the pharmaceutical/veterinary raw materials industry and some clients are saying that they prefer ...
5
votes
1answer
16k views

How much potassium permanganate is needed to completely oxidize ferrous oxalate?

Amount of substance of $\ce{MnO4-}$ required to oxidize one mole of ferrous oxalate completely in acid medium will be: (a) 7.5 moles (b) 0.2 moles (c) 0.6 moles (d) 0.4 moles In ...
7
votes
3answers
12k views

What is the origin of the colour of azo dyes?

Is it the same reason as to why transition metal complexes have colour?
3
votes
1answer
7k views

Calculate the moles of acid and conjugate base needed

Question Using the following salts listed below, calculate the moles of acid and conjugate base needed to make $V = \pu{100 mL}$ of $c = \pu{0.50 M}$, $pH \in 6.5, 6.7, 6.8$ phosphate buffer ...
8
votes
3answers
39k views

Volume required to dilute solution for a pH change

A $\pu{100 mL}$ solution of $\ce{NaOH}$ has a $\mathrm{pH}$ of $13$. What volume of water in $\pu{mL}$ must be added to change the $\mathrm{pH}$ to $11$? My steps: Begin by calculating conc. of $[\...
6
votes
2answers
269 views

Why does sweetening milk need less sugar as compared to tea?

If I have a cup of milk and a cup of tea; to get them to a sweetness I like, I usually add less sugar to the milk as compared to the tea. Why is it that milk needs less sugar to be just as sweet as ...
0
votes
1answer
291 views

Strength identification in conjugate acid-base pairing

I'm a student in highschool AP chemistry. I'm confused about a certain problem in my chem textbook. In summary, I am given a species and asked to identify its basicity as strong, weak, or negligible. ...
9
votes
1answer
953 views

Questions about Buffer System (Lab)

I will be doing a lab on Hydrogen Phosphate buffer system tomorrow and I have a few questions about the buffer system. I am not sure if my assumptions are correct. (1) What would happen to the rate ...
3
votes
1answer
159 views

Low-volatile liquids that 'ball-up' on siliconoxide or perfluoroalkanes

This is a very simple and short question. I am looking for liquids that are low/non-volatile at 20$^\circ$C (at least substantially less volatile than water) which have a high contact angle with glass ...

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