Chem help (1 Viewer)

[jellybelly59]

Hey ppl!

Couple of things i need help with:

1.Which type of fuels: solid, liquid or gas give off the most energy per gram? Why?

2.Explain how a chemist could prove experimentally that the equlibrium in a saturated salt solution was dynamic

Edit: found out question 2. Just need help with question 1 now >.<"

 

[kaz1]

This is a guess. Gas because it moves around and does not stick with it's other particles. I can't seem to express it properly.

 

[BIGTYMA]

are they all the same substance just in different phases or totally different substances all together?>

 

[lyounamu]

Gas, because due to large volume to surface area ratio, the energy is much easily released.

 

[shaon0]

For:
1) Generally speaking if the substances are similar then a gas will have more energy/gram because of its SA to Volume ratio, the energy can be more easily released. It also has weaker intermolecular bonds. So the force holding it back from combusting is less. So more energy can be released. Also takes it less energy (Activation energy) to combust.
2) Chemists can use radioactive isotopes. Since, the solution is saturated. No other ions can be dissolved into the solution unless the conditions of the chemical equilibrium is changed ie solution is supersooled and depressurised (also called a supersaturated solution). They can put a radioactive isotope into a precipitate and see using dectectors that the ions in the saturated solution are always moving/swaping places with the particles in the compound/precipitate at the bottom.

 

[lyounamu]

How can we assume that it is a same substance?

I mean if it is a same substance, how could it exist in 3 different states simulatenously?

 

[shaon0]

How can we assume that it is a same substance?

I mean if it is a same substance, how could it exist in 3 different states simulatenously?

Oh never realised that. Under different heat or pressure.
You can't really answer the question then because if the substances aren't the same then they will be prone to different explosion impacts.

 

[BIGTYMA]

How can we assume that it is a same substance?

I mean if it is a same substance, how could it exist in 3 different states simulatenously?

The op did not specify if the conditions were kept constant.

The same substance can exist in three different phases simultaneously , its called the triple point.

 

[lyounamu]

The op did not specify if the conditions were kept constant.

The same substance can exist in three different phases simultaneously , its called the triple point.

Simultaneously as in same temperature? I don't think so...

 

[Slidey]

Hey ppl!

Couple of things i need help with:

1.Which type of fuels: solid, liquid or gas give off the most energy per gram? Why?

2.Explain how a chemist could prove experimentally that the equlibrium in a saturated salt solution was dynamic

Edit: found out question 2. Just need help with question 1 now >.<"

1) most likely gas because you have a large surface area for reaction per gram (less compressed than solids and liquids).

 

[BIGTYMA]

Simultaneously as in same temperature? I don't think so...

Perhaps you should do some research.

 

[Slidey]

Simultaneously as in same temperature? I don't think so...

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

 

[BIGTYMA]

I was hoping he would do the work himself instead of blindly disagreeing with me.

Much appreciated though slidey.

 

[Slidey]

Yeah I know what you mean, but this way other people randomly viewing the thread can check it out, too.

You'd be surprised how many people think that every substance exists fully in both a homogeneous phase as well as always in thermodynamic equilibrium.

 

[kaz1]

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

That's pretty cool. You learn something new everyday.

 

[jellybelly59]

The question was given to me just like that... it's for a prac... Thank you so much ppl for your help!

 

[lyounamu]

I was hoping he would do the work himself instead of blindly disagreeing with me.

Much appreciated though slidey.

Well, if you haven't mentioned triple point or whatever, I wouldn't have known that this could have happened.

And you haven't even specified in your post whether it existed simultaneously in three phases at same temperature. I thought you meant it existed in three phases when given the certain condition for each substance.

 

[Slidey]

And you haven't even specified in your post whether it existed simultaneously in three phases at same temperature.

It does, in a heterogeneous sense.

I thought you meant it existed in three phases when given the certain condition for each substance.

Hmm? It does.

 

[BIGTYMA]

Perhaps an example is in order.

Ill use water as an example since everyone is familiar with it.

At 0.01 degrees and 0.006 atmospheres water can, and does exist as solid, liquid and gas simultaneously.

CO2 = -57 C and 5.1 atm

 

[lyounamu]

Perhaps an example is in order.

Ill use water as an example since everyone is familiar with it.

At 0.01 degrees and 0.006 atmospheres water can, and does exist as solid, liquid and gas simultaneously.

CO2 = -57 C and 5.1 atm

How would it look like? Because I have trouble imagining it. (not doubting your post)