First post, hello, I have a lot of questions.

[MigL]

Chemical compounds can be separated into 'functunal' groups.

There are acids, a sour, easily wetted substance, readily soluable in water, with an acrid smell that irritates mucous membranes, and turn litmus indicator red.
These react with bases, bitter, slippery and also water soluable, but turn litmus blue.
In modern chemistry, their solutions decompose to OH- ions and H+ ions; the log scale of their ratio gives the pH value you may have heard of.

Two other groups are oxidizers and reducers, which also react with each other, like the previously mentioned hydrazine ( reducer ) and nitric acid ( oxidizer and an acid ) used by the Germans as propellant for their WW2 rockets.
The reaction of these groups, redox reactions, are used to produce chemical energy. Think of the lead and acid in your car battery, the carbon and oxygen of a fire, or the oxygen and hydrogen that produces the thrust of a modern orbital rocket. One of the elements in the compound provides a lower energy state for one or more electrons of the other element's higher state, and this is released as useable energy.

There are other groupings that help distinguish, such as inert, or noble gases, that don't react with others, metals which have a conduction band of electrons above the valence band ( where chemical bonds are made ) and can conduct electricity and orient into magnetic domains, and even one group you may be hearing about in the news, as the American President is extorting Ukraine for its valuable rare earth elements,

Such groupings of similar properties help identify what you are dealing with, or give direction for further testing that will.

Edited 11 hours ago by MigL

[studiot]

Just now, Jack777 said:

"Metal ions in the form of chloride salt solution with platinum wire." Now, I know I'm thick, I really am. How in the world did he know it was chloride and how did he know it was platinum? These are what I'd like to know. 

 

Just now, Jack777 said:

Cool. Now, how do they know it's acid?

Sorry for so many newbie questions but this is what I've always wondered about. The simplest most fundamental questions.

No you are not thick and these are basic questions, which as you say, are fundamental.

But they are very good questions.

Don't worry we are covering these.  I hope you are taking in the new terminology. I am trying not to introduce too many new words at once.

So I think we are ready for your first chemical equation

 

ACID  plus BASE  =  (makes)  SALT plus WATER

Note that chemical equations are somewhat different than mathematical ones, although we will come to do some mathematics with them.

Such a chemical equation represents a chemical reaction (or in this case a whole class of chemical reactions)

 

So we have Hydrochloric Acid  plus Sodium Hydroxide makes Sodium Chloride plus Water.

Acids were once called spirits and hydrochloric acid was called spirits of salt.

Sodium hydroxide has a common name as caustic soda. 

So our friend either made the chlorides this way or bought them ready made.

I think MigL has described acids quite well for you. if that is not enough please ask for more.

The 'salt' created by hydrochloric acid is called a chloride.

Why chlorides ?

Well most chlorides are (very) soluble in water. That's how the presenter got the solutions.

There are always exceptions the main ones being the chlorides of silver, lead and mercury are hardly soluble.

 

So next bit of theory.

Solutions are made by dissolving a solute (sugar, salt etc) in a (suitable) solvent.

Thinking back to our earlier posts a solution is a mixture because the parts can be separated by mechanical means boiling off the solvent to leave the solute behind.
This process is called distillation.

Another similar sort of mixture is called a suspension. Here fine particles of one substances is intimately mixed with another  substance. The result is called a suspension.
This is not solution, although the suspended particles may be recovered by boiling, they may also be recovered by passing the suspension through a sufficiently fine filter.

Finally (for this post) we can also separate the solute (or part of it) by a Precipitation Reaction.

Here we take a solution of an obviously soluble salt and add a solution of a different salt which will react with the salt already in solution in such a way as to produce a Precipitate.

This happens when the added new solution contains ions that are insoluble as a salt of the original solute.

As an example we now know that silver chloride is insoluble, and I am now stating (from experience) that silver nitrate is soluble.
So if we add a soluble chloride (such as sodium chloride) to a silver nitrate solution we we observe a (white) precipitate - of silver chloride.
In effect the sodium and silver exchange their type of salt.

This sort of reaction is important in both analytical chemistry and for the preparation of chemical compounds.

The silver chloride can be filtered off or used in a second reaction as in the video.

We are now building up chemical vocabulary to use in the future.

 

 

 

 

Edited 10 hours ago by studiot
post appeared double.

[Jack777]

4 hours ago, exchemist said:

That's quite a lot already

Right. Protons, neutrons, electrons, I can understand that despite not seeing it but I take it on faith.

Atomic number and atomic weight, and isotopes. I still need a lot of work here to learn this.

Avogadro's Number and moles -  This might take me centuries to understand.

I like the study of combustion so far.

 

3 hours ago, MigL said:

Chemical compounds can be separated into 'functunal' groups.

Excellent information here but it'll take me a while to "get it." Sadly I'm aspergic so it takes me a while to grasp something but once I do it's grasped forever.

 

2 hours ago, studiot said:

No you are not thick and these are basic questions, which as you say, are fundamental.

But they are very good questions.

Don't worry we are covering these.  I hope you are taking in the new terminology. I am trying not to introduce too many new words at once.

So I think we are ready for your first chemical equation

I very much appreciate your help. And thanks for your kind words.

Yes, I have so far copied all my questions and your posts and created a document which I think I need to read and reread constantly. It's very good stuff. 

I don't think I'm ready for an equation.  About all I know is what most people know and that's H2O. One hydrogen and two oxygen. But my perennial questions are always like, ok, one hydrogen, how do they actually know it's hydrogen? Ditto for oxygen and how do they know you only need one hydrogen and two oxygen. We really need to back up and get even more basic. Like kindergarten basic  

How was hydrogen first discovered? How was oxygen first discovered? I mean, what process did they use to discover them? Was it weighing? Burning? Dunno.

But I find this absolutely fascinating. I can tell you anything you'd want to know about aircraft, how they work, how to fix them, how to fly them, same for woodworking. But chemistry? Not so much. I love studying history so anything history related in regards to who and how and when would be very helpful.

In the video you posted, he said silver nitrate. Where did he get it and how is he sure it's silver nitrate?

Same for silver chloride. How does he know it's silver chloride? And what's silver chloride used for anyway? This is so interesting!

[KJW]

57 minutes ago, Jack777 said:

he said silver nitrate. Where did he get it and how is he sure it's silver nitrate?

He probably got it from a chemical supplier, and he knows it's silver nitrate probably because that's what it says on the label of the bottle it came in. My point is that modern day chemists do not start from scratch. They (to use a well-known quote) stand on the shoulders of giants. It should be noted that knowledge of chemistry developed over time and in parallel with knowledge of physics.

I think that the scope of your questions is too large for anyone here to provide you with genuine help, as much as they may try. I recommend that you study a chemistry textbook aimed at school children. However, you may find this Wikipedia article interesting (though I haven't fully read it myself):

https://en.wikipedia.org/wiki/History_of_chemistry