Chemistry 101

[IDMclean]

Ok, I'm guessing your going to get to these eventually, but I thought I would jump the gun a little, because they happen to be something I've read about in my physics books.

 

There are two types of bonds that you haven't addressed, in addition to covalent and Ionic. They are Van der Waals and Hydrogen bonds. How do they factor in?

 

Also, why 1.6?

[Mercedes Benzene]

are two types of bonds that you haven't addressed, in addition to covalent and Ionic. They are Van der Waals and Hydrogen bonds. How do they factor in?

 

I was trying to keep it simple before. I was covering the basic intramolecular bonds. Van Der Waal and Hydrogen bonds are intermolecular bonds, and are based on how similar compounds interact with each other WITHOUT forming a new compound as intramolecular bonds would.

For instance, hydrogen bonds will form with another molecular segment of opposite polarity. This however is limited to hydrogen-nitrogen, hydrogen-fluorine, and hydrogen-oxygen interactions.

Water, for instance, is bound with hydrogen bonds of the hydrogen-oxygen variety.

I hope this helps.:thumbs_up

[Mercedes Benzene]

Also, why 1.6?

 

Because that is what Pauling said. :thumbs_up

I'm not really sure why that particular scale was chosen, but it's just like anything else: Us humans made up the number. It could have been 1743.4382

Pauling wanted 1.6

Haha.

[learnin to learn]

Van Der Waal? I have never heard of them!!!! How do they work?

 

MB I thought that you were in college! lol I guess I have a lot of catching up to do!:thumbs_up

[Mercedes Benzene]

Chemical Reactions:

 

A chemical reaction occurs when two substances come together in a manner that produces 1 or more chemically different substances. See... EASY!

 

There are 4 main types of chemical reactions (excluding isomerization and combustion which are important in organic chemistry)

 

Let's start with the 4 main types shall we?

-Single Replacement

-Double Replacement

-Synthesis (Combination)

-Decomposition

 

First:

Single Replacement reactions follow the following general equation:

ab + c --> b + ac

Notice how one element switched places and recombined with another, leaving a new lone element (;).

 

Second:

Double Replacement reactions follow the following general equation:

ab + cd --> ad + bc

In this type of reaction, the reactants completely switch places so that they are paired with a new element or compound.

 

Thrid:

Synthesis reaction follows the following simple equation:

a + b --> ab

The individual reactants combine to form one substance.

 

Fourth:

Decomposition reactions follow the synthesis inverse equation:

ab --> a + b

One substance is split into it's individual components

 

That's basically it! My next few posts will detail how to determine if certain reactions will take place based on given conditions!

Question time! <<< even though these concepts are fairly easy to comprehend :thumbs_up

[learnin to learn]

OK let me make sure I understand

 

single replacement makes an new substance, but leaves 1 lone element

 

Double replacement makes 2 new substances by switching elements

 

synthesis creates a substance out of elements

 

and decomposition tears a substance apart leaving them as lone elements.

[Mercedes Benzene]

OK let me make sure I understand

 

single replacement makes an new substance, but leaves 1 lone element

 

Double replacement makes 2 new substances by switching elements

 

synthesis creates a substance out of elements

 

and decomposition tears a substance apart leaving them as lone elements.

 

YUP! That's it!:thumbs_up

Let me clarify however, that each letter that I used to describe the equations does not have to be an element. It may also be a polyatomic ion.

[learnin to learn]

ok! al least I understand that much:)

[Chemnut]

So, Why is HF a weak acid? If you look at the strengths of the other halide acids, they increase as you go up the periodic chart. HCl is a stronger acid than HBr which is stronger than HI.

 

HF is a weak acid due to Hydrogen Bonding. Water (H20) is another example of a weak acid with Hydrogen Bonding.

[Jay-qu]

ok! al least I understand that much:)

cool, and for an example/practice question that incorparates your fire toying:

 

Carbon(in the form of cellulose and whatever else is in wood) + Oxygen -> Carbon di-oxide

 

C(s) + O2(g) -> CO2(g)

 

what type of reaction is this?

 

NOTE: States of matter are important, they give extra infomation about what is happening in the reaction. There are a few main states delt with:

(s) - solid

(l) - Liquid, used for pure substances

(aq) - aqueous, means dissolved in water

(g) - gas

 

In high school I always took chem and physics all the way through maybe 9 classes in total.. now Im in uni I had to make the choice, and it was physics. I see it as ultimately more usefull though chemistry was good fun.

[Mercedes Benzene]

Okay.

Here's my next post on chemical reactions.

This post will detail under what circumstances single replacement reactions will occur.

((Double Replacement to come soon))

 

Okay, so we already know what a Single Replacement reaction is. The lone cation switches place with the cation of a (binary) compound.

 

But how do we know when such a reaction will occur?

 

Let's take an example.

I have an aqueous solution of Copper Sulfate (CuSO4).

To this solution I add an iron nail.

So, theoretically, we have the equation: Fe(s) + CuSO4(aq) --> Cu (s) + FeSO4(aq)

The big question is, does this reaction really occur??

In this case, the answer is yes!

Here's why:

 

In the example above, the Iron cation was "strong" enough to rip the copper from its Sulfate anion.

The "strength" I just mentioned is based on the electron stability of the metal cations and metal salts involved. It is more "feasible" for the Iron to be paried with the Sulfate, than it is for the copper.

SO... how does one determine the relative activity of metals...

Easy! You look at an activity series of course!

Haha. I included an attachement in one of my previous posts that include a simple activity series.

Metals higher on the activity series are capable of taking the place of metals lower in the activity series. If you look at the chart, iron is higher than copper. Thus, iron will replace the copper in the copper sulfate compound.

It's that simple!

 

Double Replacement reactions: COMING SOON!

[Drip Curl Magic]

In September 1969 1200+ students enrolled in MSU organic chemistry/majors. 350 made it to the second term. 17 graduated BS/Chem. Elitism insists the better is preferable to the worse. Uncle Al is an elitist, as were the other 16.

 

Evolution is a hoot if you are one of the survivors.

 

wow. Those are some heavy statistics.

 

all I can do is do.

[learnin to learn]

cool, and for an example/practice question that incorparates your fire toying:

 

Carbon(in the form of cellulose and whatever else is in wood) + Oxygen -> Carbon di-oxide

 

C(s) + O2(g) -> CO2(g)

 

what type of reaction is this?

 

NOTE: States of matter are important, they give extra infomation about what is happening in the reaction. There are a few main states delt with:

(s) - solid

(l) - Liquid, used for pure substances

(aq) - aqueous, means dissolved in water

(g) - gas

 

In high school I always took chem and physics all the way through maybe 9 classes in total.. now Im in uni I had to make the choice, and it was physics. I see it as ultimately more usefull though chemistry was good fun.

It is a synthesis reaction isnt it?

[Jay-qu]

yup :)

 

The reaction would be a bit more complex because the carbon is not just simply sitting there but is locked up in carbohydrates and other combounds that make up the paper. But it is valid to simplify just the synthesis of the CO2

[quatumrulesoverall]

I was trying to keep it simple before. I was covering the basic intramolecular bonds. Van Der Waal and Hydrogen bonds are intermolecular bonds, and are based on how similar compounds interact with each other WITHOUT forming a new compound as intramolecular bonds would.

For instance, hydrogen bonds will form with another molecular segment of opposite polarity. This however is limited to hydrogen-nitrogen, hydrogen-fluorine, and hydrogen-oxygen interactions.

Water, for instance, is bound with hydrogen bonds of the hydrogen-oxygen variety.

I hope this helps.:confused:

Eh, a bit adding on, Van der Waals force, Hydrogen bonds, and London Dispersion Force are all dipole-dipole bond, which are also called intermolecular force between molecules within a quantity of compound.

Hope this helps

[Mercedes Benzene]

Eh, a bit adding on, Van der Waals force, Hydrogen bonds, and London Dispersion Force are all dipole-dipole bond, which are also called intermolecular force between molecules within a quantity of compound.

Hope this helps

 

I already talked about who they were intermolecular bonds! :lol:

[learnin to learn]

Okay.

Here's my next post on chemical reactions.

This post will detail under what circumstances single replacement reactions will occur.

((Double Replacement to come soon))

 

Okay, so we already know what a Single Replacement reaction is. The lone cation switches place with the cation of a (binary) compound.

 

But how do we know when such a reaction will occur?

 

Let's take an example.

I have an aqueous solution of Copper Sulfate (CuSO4).

To this solution I add an iron nail.

So, theoretically, we have the equation: Fe(s) + CuSO4(aq) --> Cu (s) + FeSO4(aq)

The big question is, does this reaction really occur??

In this case, the answer is yes!

Here's why:

 

In the example above, the Iron cation was "strong" enough to rip the copper from its Sulfate anion.

The "strength" I just mentioned is based on the electron stability of the metal cations and metal salts involved. It is more "feasible" for the Iron to be paried with the Sulfate, than it is for the copper.

SO... how does one determine the relative activity of metals...

Easy! You look at an activity series of course!

Haha. I included an attachement in one of my previous posts that include a simple activity series.

Metals higher on the activity series are capable of taking the place of metals lower in the activity series. If you look at the chart, iron is higher than copper. Thus, iron will replace the copper in the copper sulfate compound.

It's that simple!

 

Double Replacement reactions: COMING SOON!

 

I had to read it a couple of times, but I get it =)