Scientific terminology in English

Here is a summary of phase transitions (s = solid, l = liquid, v = vapor or gas)
freezing: l -> s
vaporization: l -> v
condensation: v -> l
sublimation: s -> v
deposition: v -> s

"Liquefaction" is a process used in the generation of liquid fuels from coal. Coal is gasified to a mixture of CO and H2, then reacted with catalysts to produce liquid hydrocarbons. I have not seen the word "liquefaction" used more generally to refer to the gas-to-liquid phase transition.

But liquefaction is only confined to the processing related to coal?

Sorry rab.
I am confused with the "Lewis Acid", could you give me an explanation?


Thanks.

Redundant.

I'm not sure liquefaction is limited to coal processing--that's just the only use of the term that I am personally familiar with. Someone else may know some other applications . . .
Regarding Lewis acids, there are three basic categories that define "acids":
1) Arrhenius acids are substances that produce H+ ions when they dissociate, such as NH4+, CH3COOH, H2SO4, etc.
2) Bronsted-Lowry acids are defined as proton donors; e.g. HCl, HNO3, etc.--they include most Arrhenius acids.
3) A Lewis acid is defined as an electron pair acceptor. I.e., a Lewis acid has an available orbital that can accommodate additional electrons. Lewis bases have lone pair electrons that are available for sharing; a reaction between a Lewis acid and a Lewis base will result in formation of a covalent bond between them. For example, BF3 is a Lewis acid, and NH3 is a Lewis base (due to the available lone pair of electrons on the nitrogen). The acid-base reaction between these two results in formation of NH3-BH3. The Lewis acid theory can be applied in cases where an acid contains no ionizable H atoms. For example, the Arrhenius and Bronsted-Lowry theories cannot explain the observed acidity of BF3, CO2, Ag+, etc. because they do not contain H+; the Lewis acid theory explains the acidity by classifying these chemicals as electron pair acceptors.
Does that help clear things up? It's a pretty complicated answer to a simple pH question 8)

All clear. Lab Rat
Lewis acid accepts election pair, and lewis base looses election pair
Your laboursome explanation is greatly appreciated.

And another question has raised from your explanation:
"electron pair"
Why you called that a "pair"?

Come on! No posts are redundant in my room :wink:

Generally, unpaired electrons (free radicals) are highly reactive and so don't last very long. If a Lewis base, etc. is stable it generally possesses a non-bonded pair of electrons, as opposed to just a single unpaired electron (there are exceptions to this, of course). For example, ammonia is sometimes written as :NH3, where the ":" indicates nitrogen's "lone pair". The lone pair resides only on the nitrogen (i.e., it is not part of a bond to any other atom).
A covalent bond consists of two electrons shared between two atoms; in the case of Lewis acid-base chemistry, a covalent bond is formed with both of the shared electrons originating from the Lewis base. The base thus shares a "pair" of electrons to form the bond between base & acid. So, for example, when :NH3 participates in Lewis acid-base chemistry, the "active" part of the ammonia molecule is the pair of electrons on the nitrogen.

That is really hard to understand.
It may take me some time to make it.
But thank you all the same, rat

Ok, a new question:

We all know that "electromagnetic waves" truly exist. And we divide them into different groups according to different frequencies:

Y-ray==B-ray==a-ray==(light?)==microwave==(I know this type of electromagnetic wave is used in radion transmission)


1. How to call this order?
2. What exactly are the names of the two types?


Thanks

The order is called the electromagnetic spectrum. The section you've labelled "light" is further divided into ultraviolet, visible, and infrared (in order of decreasing frequency). After microwave radiation comes "radiofrequency".

Thanks Rab

How to name the main parts of a round?



thanks

Circle? Sphere?

What do you mean main parts?

I'm not getting it.

Could you be thinking of the radius (distance from center to edge), the diametre (twice the radius), and the circumrefference? (pi times the diametre, distance around the circle/sphere)

Oops...

Yes, circumference, something like that.
For example, how to call the center of a round?

Btw, how to express it properly?

Does this help?

Circle

A circle is the two dimentional figure. The three dimentional one would be a sphere.

Sphere? I assumed it was called "ball" :wink:

Yes, sorry I mean circle. Thanks for the link

I have found a question in the linked page:

What is the difference between "perpendicular" and "vertical"?

Thanks.

Sphere is the mathematical term, globe is also used, but is not scientific terminology. A ball would be a spherical object, like a football for instance. Once again not scientific terminology, but much more common in regular conversation.

Vertical means a straight line up. As opposed to horizontal which is a straight line across.

Perpendicular is a straight line at right angles to another line. Like an "L" shape. Two lines at 90 degrees to one another.