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1answer
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Using Dalton's law of partial pressures

A container of volume $\pu{4.0 L}$ contains nitrogen at $\pu{25 °C}$ and $\pu{803 kPa}.$ This container is connected by a valve to another container of volume $\pu{10.0 L}$ that contains argon at $\pu{...
0
votes
1answer
2k views

Specific heat capacity and the periodic table

Can someone explain me how can I use the periodic table in order to find the specific heat capacities of some elements? (for example, of Aluminium ) The question I have encountered is as follows: ...
9
votes
1answer
138 views

Materials used in metallic glass

I've been looking over the lists of materials used together to make metallic glass. Is it purely coincidental that if you round up/down any decimals from the atomic weight of elements used to ...
3
votes
2answers
639 views

What's the name of this electrolysis device?

I've seen it in a couple of videos, it's used to electrolyze water in 2 different containers at the same time to make a comparison and thus is very handy. What is it called (besides just a ...
21
votes
3answers
6k views

What are the chemical reactions behind fire?

I've always wondered what the chemistry behind fire is. What are the basic chemical reactions behind a simple wood fire, and how do they manifest into this phenomenon?
8
votes
2answers
5k views

Which species dissociate completely in ionic equations?

I am tasked with writing a molecular equation, an overall ionic equation, and a net ionic equation for the reaction between an aqueous solution of phosphoric acid, $\ce{H3PO4{(aq)}}$ and an aqueous ...
8
votes
2answers
763 views

Proper IUPAC name of a substituted cyclohexenol

Here's the molecule: So far I've tried: 6-methylcyclohex-2-en-ol and 4-methylcyclohexen-3-ol but both are wrong. I'm rather confused as to where I should start: the alcohol or the double bond?
4
votes
1answer
6k views

Is there a way to detect bleach residue on a surface?

I was wondering if there is a way to detect for presence or residue of bleach using household items. I am curious about either chlorine-based or peroxide-based. It can be any sort of reaction that ...
-1
votes
2answers
5k views

How does Phosphorus Pentachloride bond?

The thing I am having trouble with: why does $\small\ce{PCl4}$ form a +1 ion and $\small\ce{Cl}$ a -1 ion?
2
votes
1answer
218 views

How are crystals formed from a gas?

In crystallization, crystals are formed from liquids by cooling. How can crystals be formed from a gas by cooling?
6
votes
1answer
19k views

Is there a way to calculate how fast water will cool?

Is there a way to calculate how fast water will cool if you know the water's starting temperature and temperature of the environment that you put it in, such as a freezer?
4
votes
1answer
64k views

Order of elements in a formula? [duplicate]

Possible Duplicate: Why is methane's molecular formula conventionally “CH4”, while water is “H20” (among others)? If I have a formula containing 4 hydrogen atoms and 1 ...
10
votes
3answers
10k views

Chemical reactions with a room-scale cooling effect

Are there chemical reactions that could cool down an average sized room by a noticeable amount (say 5 °C)? I would like to investigate if it is possible to have a situation where I can mix 2 ...
3
votes
1answer
3k views

What is the electron dot structure of an alkyne? [closed]

I am trying to determine the electron dot structure of an alkyne like $\ce{C2H2}$. I know that hydrocarbons with at least one carbon-carbon triple bond are called alkynes, and their general formula ...
4
votes
1answer
537 views

Shape of C₂H₂ molecule

What is the shape of the $\ce{C2H2}$ molecule? The fact that is has a triple covalent bond between the 2 carbon atoms and 2 other bonding pairs between the hydrogen and carbon atoms leads me to ...
4
votes
2answers
11k views

Boiling point of vodka

What is the boiling point of vodka? I have found the boiling point of ethanol, ~173 (degrees) F. However, I am unable to find the boiling point of vodka. I found some information on it, but I do not ...
9
votes
1answer
3k views

Options for long term storage of helium?

Specifically, if I wanted to purchase a large amounts of helium, what are my options for purchasing helium in a state that is suitable for long term storage? It's my understanding that if I were to ...
13
votes
1answer
441 views

The Evans auxiliary: rotational freedom of the benzyl group - stereoselectivity still guaranteed?

I created the L-Phenylalanine based Evans auxiliary bearing a benzyl group with help of a molecular model set and got into some questions. The structural formula will do: As I suppose a low ...
4
votes
1answer
4k views

How do I balance the combustion reaction of butene?

I have butene being burned in a fuel rich engine and I can't seem to balance this reaction: $$\ce{C4H8 + $a$(O2 + 3.76 N2) -> $b$ CO2 + $c$ H2O + $d$ C4H8 + $e$ (3.76 N2)}$$ When I try write ...
3
votes
1answer
999 views

Understanding the rate of change in titration curves

As I am looking at titration curves, a few things stand out. For now, I have a two part question: When titrating an acid with a base, for instance, the pH rises more or less abruptly around the ...
1
vote
2answers
636 views

Can caffeine be separated from coffee?

Is there a way to extract caffeine from coffee completely?
9
votes
3answers
3k views

Why does polonium form acidic oxides?

All metals form basic oxides. Metallic oxides are basic in character. Polonium is a metal, so it should form basic oxides but it forms acidic oxides. Why are its oxides acidic in character?
4
votes
1answer
425 views

How does hot tub "shock" work?

Hot tub shock is potassium peroxymonosulfate. When added to a hot tub, it creates bubbles. It is said to oxidize organic debris in the water. What is the reaction?
4
votes
1answer
358 views

Is ash fireproof?

At high temperatures (almost) everything burns to ash. Is ash 'fireproof'? Is further combustion of ash possible for example by combining with hydrogen, oxygen, etc?
5
votes
1answer
259 views

Why not "Oxygate" OO4(2-)?

So many atoms can be surrounded by oxygen atoms to make anions - chromate, phosphate, etc. In particular there's Tellurate $\ce{TeO4^{-2}}$, Selenate $\ce{SeO4^{-2}}$ and Sulfate $\ce{SO4^{-2}}$ - ...
5
votes
2answers
421 views

Energy of the n-th level for an atom

Going through the Bohr's model and his assumptions, I came across with this formula to find the energy of the n-th level of any atom: $$E = - \frac{Z k_e e^2}{2r_n} = -\frac{Z^2(k_e e^2)^2m_e}{2\...
9
votes
1answer
12k views

How is the yellow colour of nitric acid removed?

Nitric acid obtained in laboratory is slightly yellow due to the dissolution of nitrogen dioxide which is produced due to thermal decomposition of a portion of $\ce{HNO3}$. $$ \ce {4HNO3 -> 2H2O ...
22
votes
2answers
6k views

Why are atoms with eight electrons in the outer shell extremely stable?

Atoms that have eight electrons in their outer shell are extremely stable. It can't be because both the $s$ and the $p$ orbitals are full, because then an atom with 13 or 18 valence electrons would be ...
2
votes
0answers
156 views

Will the current at the inversion potential of a CV trace asymptotically approach zero?

Reading up on the theory of cyclic voltammetry, I note that the current at the inversion potential (that is, the point at which the applied potential goes negative) in every reversible CV trace I have ...
5
votes
1answer
2k views

Galvanic corrosion between nickel brass nut and stainless bolt

I am planning to install something on a boat that will be in salt water, and my question is, will the nickel plated brass fastener not corrode if I connect it to stainless steel? I looked it up on ...
2
votes
1answer
1k views

Lewis structures of H₂(C)xCH₂ molecules

I need to calculate the angles between CCC, CCH, HCH in the following molecules: ethene ($\ce{H2CCH2}$), propa-1,2-diene ($\ce{H2CCCH2}$), and buta-1,2,3-triene ($\ce{H2CCCCH2}$). If I'm not ...
5
votes
1answer
594 views

Understanding dissolution of CO₂ in Selexol and Rectisol

I'm trying to understand pre-combusiton carbon capture processes as described in this presentation. I'm told that solvents such as chilled methanol ($\ce{CH3OH}$) and dimethyl ethers of ...
7
votes
2answers
800 views

How do amines react with flue gases to absorb CO₂?

I'm reading this article about carbon capture from the combustion of fossil fuels. In this article, it says that amines are used as a chemical absorbent to capture the $\ce{CO2}$ from the exhaust of ...
8
votes
1answer
415 views

What does it mean when "a gas is dilute in CO₂"?

I'm reading an article about carbon sequestration, and I came across a strange phrase: "The flue gas is dilute in $\ce{CO2}$". I can't quite ascertain its meaning from the context. I think it means ...
4
votes
2answers
1k views

What is the correct lewis structure of SCH⁻?

I need to find the Lewis structure of the ion $\ce{SCH^-}$. I think the Lewis structure should be: $\ce{S=C-H}$, with one lone pair on the carbon and two lone pairs surrounding the sulfur. Is this ...
2
votes
1answer
520 views

Lewis structures of molecules containing oxygen

As far as I know, when writing Lewis structures for molecules, we need to consider the octet rule and the valence electrons each atom has. But, if we take for example, the molecule $ Cl O_2^- $ , we ...
5
votes
1answer
512 views

Does this set of quantum numbers have a unique solution?

I received the following question: Complete the missing values for the four quantum numbers: $n=?$, $\ell = 2 , m_\ell = 0$ , $m_s= ? $ . The problem is that I think $n$ can be any number ...
6
votes
1answer
626 views

How useful is the assumption that water doesn't auto-ionize in the following?

Now in the first row of the iCe-table, $[\ce{H3O+}]$ is said to be 0. But water autoionizes to some extent, so it shouldn't really be 0. I accept that, because the pH of this solution is 2.5, the ...
3
votes
1answer
1k views

Are there ways to predict which chemicals will kill certain bacteria?

Are there ways to compute what chemicals kill a give bacteria but not another given bacteria ? Does that help much to make medication ?
7
votes
2answers
441 views

Why do H₂ and O₂ create H₂O?

Both $\ce{H2}$ or $\ce{O2}$ are stable molecules. However when given energy they heat up and form $\ce{H2O}$. My teacher explained that the increased energy breaks the bonds, allowing new ones to form....
2
votes
0answers
112 views

Maintaining a 40% CO₂ aqueous environment?

I wish to grow algae in a 40% $\ce{CO2}$ (water under air with 40% $\ce{CO2}$ content) aqueous environment. Simple DIY methods are available, but they are generally unreliable (For more info on DIY ...
3
votes
0answers
123 views

How much of the anion species is left over after the first precipitation?

Some barium chloride is added to a solution that contains both $\ce{K2SO4}$ ($\pu{0.050 M}$) and $\ce{Na3PO4}$ ($\pu{0.020 M}$). (a) Which begins to precipitate first: the barium sulfate or the ...
6
votes
2answers
615 views

What meaning do multiple real solutions of a truncated virial equation have, if any?

Let's say I truncate the virial equation after the third term for use as my equation of state: $${P\over\rho RT}=1+B\rho+C\rho^2$$ I have tabulated values for $B(T)$ and $C(T)$. I know $P$ and $T$ ...
5
votes
4answers
2k views

Phase diagram for first 10 elements

I've been looking on the net for a reference which shows a phase diagram for elements at least from $\ce{H}$ up to $\ce{Ne}$. Specifically, I'm looking which of these elements can be solid or liquid ...
1
vote
1answer
3k views

Determining the exact charge of ions that will be formed by an atom using the periodic table

I don't know how to obtain the "exact charge of the ions" that will be formed by each atom mentioned. I also have to figure out whether they are positive or negative. Hydrogen, for example, can form ...
5
votes
1answer
950 views

What components of safety should be included in a chemistry laboratory experiment conclusion?

The focus of my question here is this: In a laboratory there is a Bunsen burner, a hot plate, hydrochloric acid, and concentrated ammonia. What would you mention about safety precautions? As students ...
3
votes
2answers
1k views

How do I find change in Gibbs free energy of water formation?

How do I find the change in Gibbs free energy of the reaction $$\ce{H2 + \frac{1}{2}O2 -> H2O}$$ when it is at $\pu{75^\circ C}$ and $\pu{1 atm}$? Do I calculate the Gibbs free energy of each ...
16
votes
2answers
22k views

Why does hand sanitizer turn into a liquid after coming out of the bottle?

Hand sanitizer is a gel in its bottle, but when I pour it on my palm, it turns into a free flowing liquid. Why does that happen? It doesn't turn to a liquid when I pour it on my floor or my table. ...
21
votes
4answers
24k views

Why are equilibrium constants unitless?

I haven’t quite reached the point where I can read a full-fledged text on chemical kinetics and thermodynamics yet, so bear with me, please. I’m wondering why a value like $K_\text{eq} = \frac{[\ce{...
1
vote
1answer
486 views

What causes reactions to react the way they do?

We were taught that there are primarily four kind of reactions, synthesis, combustion, single displacement, and double displacement. When the reactants are given to you, the reaction can be predicted. ...

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