2010 HSC Chemistry Revising Marathon (2 Viewers)

[hello-there]

higher temperatures favour an increase in reaction rate as the molecules have higher kinetic energy and can overcome the activation energy barrier

other factors include adding a catalyst


write an ionic equation to represent the ionisation of the acid formed when SO2 gas dissolves in water

I think its

SO2 + H2O ----> H2SO4
Ionic equation is:
Net ionic : S-2 2O-2 + 2H+ O-2 ------> 2H+ + SO4 -2

hmmm can someone confirm this (also is this a complete ionic equation as well)

I dont have a question but i would love a multiple choice or calculation question

 

[random-1006]

I think its

SO2 + H2O ----> H2SO4
Ionic equation is:
Net ionic : S-2 2O-2 + 2H+ O-2 ------> 2H+ + SO4 -2

hmmm can someone confirm this (also is this a complete ionic equation as well)

I dont have a question but i would love a multiple choice or calculation question

i think S should be +4 ( i could be wrong)

 

[random-1006]

100g of glucose was fermented and after one day the mass of the fermentation vessel had decreased by 35g . Assuming the mass change is due to carbon dioxide alone, calculate the theoretical volume of dry carbon dioxide produced at 25 C and 100kPa ( thats an easy one, ill put up another)

 

[random-1006]

5.2g of Zn was completely dissolved in dilute HCL and the gas collected at 25 C and 100kPa.

Calculated the volume of gas produced

(again easy) lol, i wont put up any more

 

[iMAN2]

5.2g of Zn was completely dissolved in dilute HCL and the gas collected at 25 C and 100kPa.

Calculated the volume of gas produced

(again easy) lol, i wont put up any more

Always write down the equation:
Zn+2HCl ----> H2+ZnCl2

n=m/M
n=5.2/65.41
=0.079.. moles (2 dp)

Note that I have kept this value in the calculator so I can use it for further calculations i.e. 0.0794985... etc however, for the purposes of working out have rounded it down to 2 decimal places.

As Zn and H2 react and form in equal ratios, H2 is formed in equal moles:

0.079.. moles. (2 dp)

1 mole occupies 24.79L at RTP (25C and 100kPa)

0.079 x 24.79

=1.97L (2 dp)

 

[hello-there]

OK i got a question.

Define: equilibrium constant
& Reaction quotient

What are the differences between the 2.

 

[nat_doc]

to add:
Increasing pressure

that only does something when gasses are involved

 

[nat_doc]

OK i got a question.

Define: equilibrium constant
& Reaction quotient

What are the differences between the 2.

i don't think thats in the course but i remember reading about it

equilibrium constant: this is a figure which gives an indication of which way the eqib position has shifted.

Reaction quotient: this is the instantaneous equilibrium constant (they have the same formula)

the difference is if it is at that slip second(rq) or generalised(ec)

NEW yr 12 Question (i made this one up):

a)Define a weak acid :
b)despite critic acid being a weak acid, in which it doesn't completely dissociate(lol i know i just defeated the purpose of part a)), how it is possible to preform a successful titration. use equations to explain your answer

New Q: this is from yr 11... but i heard that they can test us on yr 11 stuff...

2 cubes of different metals were heated to 100 degrees. they were placed on ice. after 30 mins, cube A sunk deeper than Cube B... what property of the metals can be deduced from this ?

HINT do u know german? yticapac taeh cificeps \HINT

 

[random-1006]

i don't think thats in the course but i remember reading about it

equilibrium constant: this is a figure which gives an indication of which way the eqib position has shifted.

Reaction quotient: this is the instantaneous equilibrium constant (they have the same formula)

the difference is if it is at that slip second(rq) or generalised(ec)

NEW yr 12 Question (i made this one up):

a)Define a weak acid :
b)despite critic acid being a weak acid, in which it doesn't completely dissociate(lol i know i just defeated the purpose of part a)), how it is possible to preform a successful titration. use equations to explain your answer

New Q: this is from yr 11... but i heard that they can test us on yr 11 stuff...

2 cubes of different metals were heated to 100 degrees. they were placed on ice. after 30 mins, cube A sunk deeper than Cube B... what property of the metals can be deduced from this ?

HINT do u know german? yticapac taeh cificeps \HINT

the stuff about equilibrium constants and such is in industrial chem option ( which i didnt do, i did shipwreaks)

Its good that you are making questions up by yourself, very good way to learn and test yourself.

lol you dont need a hint on the yr 11 one, its fairly easy i think (even though there is a hidden trick in there), and IF they test yr11 stuff it will only be for 1% of the paper ( and most likely in multi choice where you already have 1/4 chance of guessing correctly), you are far better knowing yr12 back to front before you worry about yr11

 

[nat_doc]

... you are far better knowing yr12 back to front before you worry about yr11.

yeh lol, i just remember seeing that when i was studying for chem in yr 11 and i always remembered it... seemed cool

 

[nat_doc]

come one pepz.. lets keep the ball rolling! Trials are in a few weeks!

 

[hello-there]

Industrial chem topic:
Q. Discuss the issues with the increased use of wood and evaluate the progress being done to resolve the issues.

First of all discuss means to provide advantages and disadvantages
but for this question do they only want disadvantages?

 

[hello-there]

Heres another qwirky question:
In a galvanic cell a voltmeter is usually attached,
how can electrical energy flow through the external wires to the other electrode if a voltmeter has infinite resistance

 

[hello-there]

Heres another qwirky question:
In a galvanic cell a voltmeter is usually attached,
how can electrical energy flow through the external wires to the other electrode if a voltmeter has infinite resistance

and how can ions in the electrolyte solution replace the loss of electrons in a galvanic cell

 

[random-1006]

Heres another qwirky question:
In a galvanic cell a voltmeter is usually attached,
how can electrical energy flow through the external wires to the other electrode if a voltmeter has infinite resistance

i think thats more of a physics question

 

[hello-there]

ok redirecting post

 

[richman92]

i think it is not a voltmeter but actually a galvanometer (a ampermeter) which measures the current

 

[hello-there]

in text books they have a voltmeter.
Anyways next question:
Q. One use of sodium carbonate is glass making. Provide an equation to represent this.

 

[hello-there]

in text books they have a voltmeter.
Anyways next question:
Q. One use of sodium carbonate is glass making. Provide an equation to represent this.

 

[random-1006]

in text books they have a voltmeter.
Anyways next question:
Q. One use of sodium carbonate is glass making. Provide an equation to represent this.

is that prelim, i dont remember learning that