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Offline Zetiam

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need to turn this in tomorrow T_T
« on: March 31, 2008, 08:42:02 PM »
So.. i have tried almost everything tryng to figure this out by reading in the internet and tryng to find the answers on google and etc and with no results at all and those links got me confused so i will just post it here it's some question for my chemistry homework due tomorrow,i did my homework.. this are just some questions i dont get and cant be found on my notes so im not lazy uhh need help plzz ;D
Questions are:

Particles within a solid
a) vibrate b)vibrate weakly about fixed positions
c) vibrate energetically d) exchange positions easily

What happens when the average energy of a liquid particles decreases?
a) vaporizations b) a disorderly arrangment
c)evaporization   d) freezing

the Energy of the particles in a solid is..

What causes the high density of solids.

Molescules at the surface of a liquid can enter vapor phase only if..

Why is water molecules polar?

molecules substances contain?

Physicals mean can be used to separate..

Does Fe(No3)3 and MgCl2 produce a precipitate when combined if no why.

bonus question:

How many grams of glucose must be added to 550 grams of water in order to prepare a solution whose boling point is 101.1C?

Offline agrobert

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Re: need to turn this in tomorrow T_T
« Reply #1 on: March 31, 2008, 08:54:54 PM »
The solid-liquid energetics questions are answered in your textbook and should be intuitive.  Does a solid move?  Does a liquid flow?  Do things moving/disordered have more or less energy than static objects?  Use process of elimination for multiple choice.  I don't think you have tried hard enough.

Polarity of water

Precipitate Question
should also be available in your book.


Good luck
In the realm of scientific observation, luck is only granted to those who are prepared. -Louis Pasteur

Offline Zetiam

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Re: need to turn this in tomorrow T_T
« Reply #2 on: March 31, 2008, 09:03:54 PM »
Thank's for the reply but sadly i cant find to figure out the answer just by reading in those sites, its too much i cant handle this is my sohpmore year in hs and im poorly failing do you mind like giving me answers and then explain because in like explain it please. is the answer for the first one  c?
 and for teh second one a?

Offline boostar

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Re: need to turn this in tomorrow T_T
« Reply #3 on: April 01, 2008, 06:23:09 AM »
Heh I remember how stressful it could get when I always did things on the last day: the best tip is plan everything out, get a diary and do things well in advanced :P Regarding all your questions, that is a lot to do for one day... what were you thinking? It is like half a terms worth of work.

I'll help you, but make sure you read agroberts websites first. Also, never ask for the answers without showing that you have tried first... it's bad conduct :P

Particles within a solid
a) vibrate b)vibrate weakly about fixed positions
c) vibrate energetically d) exchange positions easily

Unfortunately for you I'll have to agree with agrobert here, and his hint is really...well um obvious. You should be processing his hints into your head... does a liquid flow? Yes... Do things moving have more or less energy than static objects?This is your cue to think about this -> If you're just standing still, will you be using more or less energy than when you are actively moving ie. running a 100m race? While this is a poor example, it should be able to illustrate that things that are moving have more energy than things that are static. Therefore, if the table your computer is on isn't moving, and the air you breathe is constantly moving around you... what does this suggest? Which one of these has more energy in its particles? This should give you enough information, as agrobert said, to use the process of elimination to find the correct answer.

You can now use the knowledge you hopefully have learnt to answer the first question correctly to answer the next question. Think about it: if I have a liquid, and I am decreasing the energy in its particles - what is happening? If you are running, and you are slowly coming to a stop - what will be the end result? Will you not come to a stand still eventually - and won't the overall energy you expend be less? Once you have this basic understanding, ask yourself the question: which processes require an increase in energy, and which processes require a decrease?

The next question should be obvious after everything I have went through.

High density of solids -> think about particle movement and particle arrangement in a solid.

The next question -> particle energy once again. Hint: vapor phase requires energy.

Water molecules polar? -> Read the wiki article. I'll help you with this because I think your teacher probably hasn't gone through all the concepts there. I'll quote form the article:
"Electrons are not always shared equally between two bonding atoms: one atom might exert more of a force on the electron cloud than the other. This "pull" is termed electronegativity and measures the attraction for electrons a particular atom has. "
Hint: Oxygen is the more electronegative element in water. (ie. it pulls electrons away from hydrogen to itself) Therefore, if one element has more electrons (ie. negative charges) than the other elements, what will happen in terms of charge? This one is tricky if you lack basic understanding of concepts... so good luck :p

The next two 'questions' do not make sense.

The question about solubility: agrobert has basically delivered the answer into your lap! What more could you want? I'll give you the benefit of the doubt and assume that you forgot to figure out the species in the compound. Honestly, just read it off the chart.  ;)

Finally, actually -read- the bonus wikipedia entry. hint: boiling point of water = 100oC

Offline Zetiam

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Re: need to turn this in tomorrow T_T
« Reply #4 on: April 01, 2008, 07:49:46 PM »
Well,  i'd let you know tomorrow what i got in my test

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