Hsc Marathon 2009 - Chemistry (2 Viewers)

[gifted:)]

alkanols are a sub group class of compounds called alcohols. they contain the -OH functional group. an example is ethanol - C2H5OH

Q. why is it necessary to produce technetium-99m at or close to the hospital using it?

im so sorry im so bad at this

 

[gifted:)]

I am soo slow at typing! Lol

 

[Kaatie]

a condensation polymer is a long, chain compound formed when monomer molecules join together forming a polymer and releasing a small molecule such as water eg. cellulose, nylon, polyester, cotton, cellophane and dacron.

because of its short half life?

describe the production of 2 transuranic elements. Include equations.

 

[gurmies]

You guys are correct =) - Sorry I can't answer the question though Kaatie, because I haven't learnt that yet

 

[Kaatie]

okay, different qquestion than.

Identify properties of Biopol

 

[shady145]

biopol is biodegradable, making it useful for conatiners thast only have short uses. it is insoluble in water, permeable to oxygen, resistant to UV light, acids and bases, soluble in chlorinated hydrocarbons, high melting point, high tensile strength, more dense than water, non toxic.
hehe these are a list from a work sheet my teacher gave to me...


Q. define biomass, and what is the major chemical component of it.

 

[gifted:)]

Biomass is material produced by living organisms; mainly it is plant material though the term also includes animal excreta and material made by algae. Cellulose is the major chemical component of biomass.

Q. what are the two processes for breaking cellulose into glucose?

 

[Kaatie]

1. using cellulase enzymes
2. Using a strong, concentrated sulfuric acid solution

.... is that right?

explain dispersion forces

 

[marcquelle]

dispersion forces is the amount of attraction that one atom has towards another based on the mass of the atom. Therefore the smaller the atom the greater dispersion forces as for the outer atom is closer the second and requires more energy to remove the atom.?

i'm not going to post a question cause i think i got this question wrong. If i have please please correct.

 

[marcquelle]

1. using cellulase enzymes
2. Using a strong, concentrated sulfuric acid solution

.... is that right?

explain dispersion forces

can't concentrated phosphoric acid also be used?

 

[aero135]

yes mate!

 

[shady145]

dispersion forces is the amount of attraction that one atom has towards another based on the mass of the atom. Therefore the smaller the atom the greater dispersion forces as for the outer atom is closer the second and requires more energy to remove the atom.?

i'm not going to post a question cause i think i got this question wrong. If i have please please correct.

yea thats right i think.
i woulda just said they are the weakest intermolecualr forces that attract molecules of the same family. ask another question one coz there isnt one going

 

[marcquelle]

explain redox in detail

 

[Kaatie]

as in redox reactions?

 

[marcquelle]

yeah

 

[arjungamer123]

dispersion forces is the amount of attraction that one atom has towards another based on the mass of the atom. Therefore the smaller the atom the greater dispersion forces as for the outer atom is closer the second and requires more energy to remove the atom.?

i'm not going to post a question cause i think i got this question wrong. If i have please please correct.

Technically you can't say mass of the atom.

Dispersion forces are created by the random movement of electrons in an atom; in such a way as to attract atoms together. Therefore, the greater number of atoms present in the molecule; more the dispersion forces.

So "mass" in the chemical term(p+n) has no effect on the whole thing.



________________________

Answer to new question:

In a redox reaction; there are two parts of the reaction. The reduction and the oxidation. In oxidation, a neutral species atom loses it's electrons, thereby changing into an ion. Whereas; in a reduction reaction, an ion gains atoms to become a neutral species atom.

Therefore; a redox reaction is a reaction in which electrons are transferred from one substance to another. Depending on the spontaneity of the reaction; the reaction may yield an electromotive force, which forms the basis of electrochemistry and galvanic cells.

Sample redox:

Zn + CuSO4---> ZnSO4 + Cu
Zn----> (Zn^2+)+ 2e^-
(Cu2+ ) + 2e^- ----> Cu



New Question:

Explain Fermentation in terms of its chemistry; and give 2 ideal conditions needed for the production of ethanol.

 

[bored of sc]

Fermentation is where carbohydrates such as glucose and starch are chemically converted into other industrially/commercially viable substances such as ethanol and by products including carbon dioxide. Fermentation requires yeast catalysts which produce enzymes needed to convert the starting material. Ethanol is produced via the fermentation of glucose expressed in the following reaction:
C₆H₁₂O₆(aq) --> (yeast cat.) 2C₂H₅OH(aq) + 2CO₂(g) + heat
The process is exothermic.
Two ideal conditions for this reaction are:
> a constant temperature (37^oC)
> anaerobic (air-free).

Is that enough detail? That's all I know.

 

[bored of sc]

New question:

Indicators can be used to test the pH of the following:
(a) Soil
(b) Swimming pools
(c) Aquariums
(d) Water testing of streams, lakes and rivers

For each part:
(i) Why is it important to test the acidity?
(ii) What can be done to correct the situation if the test result indicates that the substance is too acidic or too basic?
(iii) How is the test performed (as in the use of indicators)?

 

[Aerath]

can't concentrated phosphoric acid also be used?

Yes, it can.

 

[H4rdc0r3]

dispersion forces is the amount of attraction that one atom has towards another based on the mass of the atom. Therefore the smaller the atom the greater dispersion forces as for the outer atom is closer the second and requires more energy to remove the atom.?

i'm not going to post a question cause i think i got this question wrong. If i have please please correct.

dispersion forces are created by the movement of electron clouds in orbit around the atom's nucleus.. pretty much as they move around, they form temporary dipoles with the nucleus of other atoms causing the attractive force. Thats why the higher the molecular mass, the more electrons there are and the stronger the attractive force as more momentary dipoles are being formed.