@Loong how to include ppb

As @Loong I have already got themass of Hg

If I have a compound that has H and Na which would go first?

I'm trying to combine Sodium, Chloride, Hydrogen2, Oxygen

@Alex CH_2OS I imagine, but I only started learning some chemistry 4 days ago

The Hill system says Carbon, then hydrogen, and then alphabetically ordered I think

@Alex HNa I mean* (Since that was the thing you wanted to order)

(Although you had only 2!=2 things to try in google, "HNa" "NaH")

Hi there Chat!

It's been explained to me that the reversed electronegativity trends around the middle of the periodic table (EN increases downwards in groups 10-13 (and somewhat at the bottom of 15)) is a result of not only the decrease in ionic radius from what would be "expected" due to the lanth-/act-inide contractions, but also because of the effects of relativistic quantum mechanics

Can anybody suggest any general reading on the latter subject, specifically in its application explaining the reversed electronegativity trend (especially in groups 11 and 12)>

?

The inspiration of this formula might be from the memory of the Madelung constant mixed up with nuclear charge and some coloumb stuff

methane is a stronger acid than water :o

@Alex Assuming that it is sodium hydride, it is NaH.

@Alex what do you mean by combine?

@JackDon 1. S is sulfur not sodium. Sodium is Na. 2. That thing doesn't exist.

@user123733 You know the mass of the solution: 14.97 kg = 14 970 g

However, this solution is mainly water. It contains only a small trace of mercury.

The concentration of mercury is given as 1.68 ppb.

This "ppb" is just a dimensionless factor like "%". Its value is 1 ppb = 1 × 10^(−9).

Therefore, the mass of mercury in the water sample is m = 14 970 g × 1.68 × 10^(−9) = 2.51 × 10^(−5) g.

> Disregard any peak with w/w less than 0.05%

what is w/w in chromatography?

@Loong thanks a lot

@CowperKettle weight / weight

(concentration by mass)

I'm trying to connect a USB laser printer to Windows 7, and the windows printer connect master shows no USB port. It says "select printer port" and shows LPT1 etc. O_O

How does the ring not open after the formation of para-bromobenzyl cation?

Hello there

I'm making a game about chemistry, atoms and molecules

You search atoms on planets and such

And there is a simple problem

Some atoms are never found in space

(i mean in our knowledge)

And how could I estimate the energy needed to make new atoms by nuclear fusion ?

I mean, making new atoms (human-made) would need huge amounts of resources in energy

@PearlSek For the light elements (up to about iron) you would get energy by fusion.

You can look at the nuclear binding energy per nucleon.

@Loong @orthocresol how do you do hydration of carbon-carbon double bonds in basic medium?

@PearlSek raw data can be found here: einstein-online.info/spotlights/binding_energy-data_file/…

To make elements heavier than iron, you would need something like the r-process.

@Jan I was about to answer the retro-aldol. :(

@DHMO I already mentioned it in my comment: it is a conjugate addition.

Anyway, your mechanisms are always a bit off. If there is some reaction involving some C-H bond, such as a deprotonation, then you have to draw out the single bond. You can't leave it as a CH2 and CH3 and just draw arrows to it.

Furthermore, in this case, if you are assuming the reaction to be in NaOH/H2O (for example), the carboxylic acid should be permanently deprotonated.

Small things like these add up. But perhaps the most glaring bit is the C-H bonds not being drawn out.

@orthocresol As if the simple closing of a question could stop you! ;D

@Jan like this one? chemistry.stackexchange.com/a/65235/7951

I was thinking more about using the @ortho­mjölnir twice, but if you want to share that option …

@Jan Are you suggesting mod abuse? :D

=O It has been said! Run!