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HSC 2012-2015 Chemistry Marathon (archive) (2 Viewers)

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Drsoccerball

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re: HSC Chemistry Marathon Archive

I got one in my chem trial, so I don't see any reason there shouldn't be one in the HSC
We had two choices and we didn't have to pick a galvanic cell...
 

Ekman

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We had two choices and we didn't have to pick a galvanic cell...
What? I don't think you are talking about the same question as I am. Because the question was about testing metals, and if you didn't talk about galvanic cells, well im not sure how you would get the marks. In fact the marking criteria were talking about galvanic cells, there wasn't any choice about it...

The only choice you had to make is whether you put down a qualitative or quantitative method for the testing. (I put both in the exam, I had a little extra time)
 
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Drsoccerball

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What? I don't think you are talking about the same question as I am. Because the question was about testing metals, and if you didn't talk about galvanic cells, well im not sure how you would get the marks. In fact the marking criteria were talking about galvanic cells, there wasn't any choice about it...

The only choice you had to make is whether you put down a qualitative or quantitative method for the testing. (I put both in the exam, I had a little extra time)
I did galvanic cell but the girl coming first in chem who got full marks used the idea of displacement reaction to determine which metals more reactive which is what you were suppose to do. (Since the question said no additional chemicals can be used)
 

BlueGas

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It gave four random metals and asked to develop a procedure to determine which one was more reactive.
So how would you develop a procedure to answer this question?
 

el_manu

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I did galvanic cell but the girl coming first in chem who got full marks used the idea of displacement reaction to determine which metals more reactive which is what you were suppose to do. (Since the question said no additional chemicals can be used)
What does that even mean?
 

Drsoccerball

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So how would you develop a procedure to answer this question?
Well what i did was use a galvanic cell with the highest oxidising agent which i picked to be chlorine. Then i said connect the galvanic cell to a galvanometer and the one that produces the highest value is more reactive etc... And i lost 2 marks for not giving quantities of liquid and also because my experiment wasnt "safe" since it said in the question "outline a safe experiment...
 

Mr_Kap

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Which Hydrocarbons are gases at room temperature?
 

Drsoccerball

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Which Hydrocarbons are gases at room temperature?
Usually the ones with less carbons and hydrogens have a higher probability of being gases at room temperature.
 

Ekman

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Which Hydrocarbons are gases at room temperature?
Id say that due to the lack of hydrogen bonding, and because of the weak dispersion forces, hydrocarbons would have lower melting a boiling points. And as drsoccerball said, smaller chain hydrocarbons are more likely to be gases, and this ties back into the point about having weaker dispersion forces, due to their lower molecular weight.
 

Mr_Kap

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Id say that due to the lack of hydrogen bonding, and because of the weak dispersion forces, hydrocarbons would have lower melting a boiling points. And as drsoccerball said, smaller chain hydrocarbons are more likely to be gases, and this ties back into the point about having weaker dispersion forces, due to their lower molecular weight.
Thx.

So like C1 to C5 Hydrocarbons then?
 
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Describe the structure of cellulose, relating to its properties.
Cellulose is a condensation polymer and a biopolymer made of B-Glucose monomer units, which flip upside down every second glucose. Due to hydrogen bonding present within the molecule, cellulose is insoluble because the intermolecular forces cannot be easily broken. Because ever second glucose unit is flipped upside down, a reasonably linear molecule is produced, increasing the density and strength of the molecule.
 
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Does the water molecule only have hydrogen bonding intermolecular forces or does it also have dipole dipole forces - some websites say it does and some say it doesn't so I'm a bit confused. I originally though water doesnt have dipole dipole forces because its a symmetrical molecule...
 

Drsoccerball

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Does the water molecule only have hydrogen bonding intermolecular forces or does it also have dipole dipole forces - some websites say it does and some say it doesn't so I'm a bit confused. I originally though water doesnt have dipole dipole forces because its a symmetrical molecule...
both
 
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