States Of Matter -Chemistry -Weird thing :S

[ana_mujahid]

Sallam/Hi

On my spec' it says:

-Discuss the states of matter in terms of kinetic theory

on both my GCSE and IGCSE books ive found nothing :S:rubeyes:

what does it mean, and can u explain it for me :)

thanks

[Mace]

See if this helps:

http://chssciences.homestead.com/KineticTheory.html

Specifically this section:

"The states of matter depend on the relative motion of the molecules making up the substance. If they have little kinetic energy, they have a very small range of motion. These atoms and molecules vibrate about a fixed point. As energy is added, the kinetic motion increases until the molecules simply can't vibrate any faster. As we continue to add energy the temperature or average kinetic energy can't increase but the bonds become looser and eventually the molecules are able to expand enough to slide past each other. The heat or energy that doesn't increase the temperature, but is used to loosen the bonds, is called "latent" or hidden heat. These loosely held molecules constitute a liquid. After the bond is loosened, the molecule is able to move faster until it eventually reaches a point where it can't move any faster. As the energy is added to this liquid, it eventually breaks the bond and the molecules are free of one another. This is a gas. Again, the "latent" heat causes bonds to break, not temperature to rise. A graph of this action reveals a stair step pattern to the action."

[ana_mujahid]

so:

solids - The particles vibrate about their positions – the hotter the solid becomes, the more they vibrate (causing solids to expand slightly when heated)

liquids - The particles are constantly moving with random motion. The hotter the liquid get, the faster they move. This causes liquids to expand slightly when heated.

gases - The particles move constantly with random motion. The hotter the gas gets, the faster they move. Gases either expand when heated, or their pressure increases.

[Mace]

so:

solids - The particles vibrate about their positions – the hotter the solid becomes, the more they vibrate (causing solids to expand slightly when heated)

liquids - The particles are constantly moving which random motion. The hotter the liquid get, the faster they move. This causes liquids to expand slightly when heated.

gases - The particles move constantly with random motion. The hotter the gas gets, the faster they move. Gases either expand when heated, or their pressure increases.

That's good.

I would add that liquid motion is not as random as gaseous motion. A better way to say it would be that the molecules slide against each other. Whereas in a gas, the molecules are moving basically independently.

The key point to understand is that it takes energy to loosen the bonds as you move from solid -> liquid -> gas.

[ana_mujahid]

That's good.

I would add that liquid motion is not as random as gaseous motion. A better way to say it would be that the molecules slide against each other. Whereas in a gas, the molecules are moving basically independently.

The key point to understand is that it takes energy to loosen the bonds as you move from solid -> liquid -> gas.

hmm yes its not as random as gaseous motion.

ok thanks again mace i can always depend on u for help in my maths and sciences :up:

[ana_mujahid]

sry, i also noticed this on my spec' and once again its not stated in my books:


Explain how heat of vaporisation can be used to compare the energy needed to separate the same number of different particles

[Mace]

So heat of vaporization is basically the amount of energy needed to boil some particular quantity of liquid.

So for example water has a heat of vaporization of 40.7 kJ/mol. Meaning 40.6 kJ of energy is needed to boil a mol of H20 molecules.

Other substances have different heats of vaporization. Ammonia is 23.4 kJ/mol.

Hydrogen required just a tiny fraction of that (0.45 kJ/mol)

More information can be found at:

http://en.wikipedia.org/wiki/Enthalpy_of_vaporization

[ana_mujahid]

thanks

[GAL-actic]

I have my exam next week...about polymers:nervous:

[ana_mujahid]

I have my exam next week...about polymers:nervous:

insha'ALLAH u will pass, good luck :up: r u GCSE or A-lvls?

[GAL-actic]

insha'ALLAH u will pass, good luck :up: r u GCSE or A-lvls?


Thanks.

It's a bit different here...but I've done GCSE and now I'm in uni.

[ana_mujahid]

Thanks.

It's a bit different here...but I've done GCSE and now I'm in uni.

cool

2 years till im in uni :rolleyes: i wonder how uni life is?:rolleyes: