There are 2 phase diagrams I learned during chemistry tuition class today.
Ok, firstly, let me explain phase diagram for a typical substance(x).
As shown in the figure above, a phase diagram is plotted as pressure against temperature.
There are 3 bold lines in the figure, which are Red, Green and Blue. And there are 3 areas within the 3 lines.
As shown, the left portion of the phase diagram is a substance exist in solid(S) state, while middle is in liquid(L) state; right portion is gaseous(G) state.
The Red line represent solid and gas exist in equilibrium, which means the amount of solid of substance (x) = the amount of gas of substance (x).
The Green line represent solid and liquid exist in eqilibrium; while the Blue line represent solid and gas exist in equlibrium.
There are 2 points in the phase diagram. The Triple point is the point where S,L&G exists in equilibrium; while the Critical point means that L&G are indistinguishable, which means we can see substance (x) as in gaseous state only.
After that, I learned about the phase diagram of Water & Carbon Dioxide.
Water has a special kind of phase diagram i.e the Green slope has a negative gradient (typical substance has the Green slope as positive gradient, as shown in diagram).
Water has its triple point at 0.006atm and 0.01*C. At 1atm, water has a melting point of 0*C and a boiling point of 100*C. And its critical point is er..er.......I forgot edi...paiseh >< (I can't find the phase diagram of water in wikipedia, so just imagine the Green slope of the diagram shown has a negative gradient, that is the phase diagram of water)
When we increase the pressure beyond 1atm, we found that the melting point of water decreases but the boiling point of water increases.
Therefore, the higher the pressure, the more readily for the water to change its phase from S>L.
Next is the phase diagram of Carbon Dioxide. Carbon dioxide has a typical phase diagram, which means the shape of the phase diagram of Carbon Dioxide is almost the same as the phase diagram shown in the figure.
CO2 has its triple point at 5.1atm and -57*c and Critical point at 73atm and 31.1*C.
Carbon dioxide can only exist as S&G at 1atm (normal pressure), it need a pressure as high as 5.1atm only can change to liquid, that's why Solid CO2(dry ice) sublimes(S>G).
When we increase the pressure of CO2, we found that the melting point and boiling point of CO2 increases.
Therefore, the higher the pressure, the more difficult for the CO2 to melt.
There are more about the phase diagram but I found it to be hard to write in here. So I think I'll just stop here.
This is just a subtopic of chemistry form 6 under chapter 1 only and there are so many things to learn and hard to understand too(I mean your brain need to really 'turn' and digest it before you can really understand).
Actually writing something here of what I've learned can really help me to reinforce my memory and it can be my revision note too! haha.. As I am the one who actually can 100% understand of what am I writing.
But some of it really hard to write it out in words la..So, if I see something that I think I am able to write it out in words, I'll write it here! haha..that's quite fun and interesting~ this also makes me to 'hope' for a new knowledge to write it here!
Hope I can continue on this for the next thing I learn.^^
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