Chem Log Books (1 Viewer)

[roundy]

Hey everyone...

First time here, but seems like it might help out...

just wonderin if anyone has done summin called a log book, where you get one part of the syllabus to do n u do it urself...

if so, has anyone done one for the topic water in year 11, this could really help me out, any info would be much appreciated!!!

thanx,
roundy

 

[roundy]

NOTE: i only want a nudge in the righ tdirection, NOT THE ENTIRE THINGY!!!

 

[Emma-Jayde]

How much do you need and on which syllabus points specifically? I've got syllabus dot point books for every topic for 11 and 12 except the prelim metals topic.

 

[roundy]

well, just water... thats it, point 5.2, the equation one, the last set of points, set number 5

 

[Emma-Jayde]

Ahhh the specific heat capacity, endo/exothermic reactions and ΔH = -mCΔT part?

 

[Dreamerish*~]

I'm in love with MCΔT.

 

[roundy]

yes, sorry bout the lack of explanation...

yes, thats the part that im havin troubles with

any help would be much appreciated...

thanx,
roundy

 

[Dreamerish*~]

Um... I can tell you a thing or two about ΔH.

ΔH = MCΔT

ΔH = total energy released, in joules (J).
M = mass of water used (g).
C = constant for the heat capacity of water - usually 4.18 or in some textbooks 4.2.
ΔT = change in temperature

You can use kJ and kg for ΔH and M respectively, but make sure that the two units agree with each other - that is, only use J with g, and kJ with kg.

 

[roundy]

thanx very much

 

[tennille]

If ΔH is in kJ/mol, then you must divide the answer from the above equation by the amount of moles there are of the substance. If it's kJ/g, then you have to divide it by the amount of substance there is in grams.

 

[Emma-Jayde]

Specific heat capacity is the amount of heat energy required to raise the temperature of 1g of a substance by 1 degree C


A reaction is exothermic when the heat absorbed during dissociation* is less than the heat released during hydration. **
ΔH_solution is negative and the temperature rises

A reaction is endothermic when heat absorbed during dissociation is greater than the heat released during hydration.
ΔH_solution is positive and the temperature falls

*Heat is absorbed to break bonds
**Heat us released when bonds are made

 

[roundy]

thanx for the help everyone, i suppose u all know what its like to be struggling with a question/topic

 

[Dreamerish*~]

Damn straight we do. Wait till you do nuclear chemistry. *Sigh*

 

[Emma-Jayde]

Nuclear chemistry
BANG!!!
No...Wait...that's more like nulear physics...
But anyway...I liked the nuclear chem part!

 

[~ ReNcH ~]

Damn straight we do. Wait till you do nuclear chemistry. *Sigh*

Hmm..nuclear chem is ok.
If I were to choose a topic I'd say Electrochemistry is probably the most difficult part of the syllabus to get the hang of...but after a bit of reading and revising it's ok.