Warning: Illegal string offset 'html' in /home/hsn/public_html/forum/cache/skin_cache/cacheid_1/skin_topic.php on line 909

Warning: Cannot modify header information - headers already sent by (output started at /home/hsn/public_html/forum/cache/skin_cache/cacheid_1/skin_topic.php:909) in /home/hsn/public_html/forum/admin/sources/classes/output/formats/html/htmlOutput.php on line 114

Warning: Cannot modify header information - headers already sent by (output started at /home/hsn/public_html/forum/cache/skin_cache/cacheid_1/skin_topic.php:909) in /home/hsn/public_html/forum/admin/sources/classes/output/formats/html/htmlOutput.php on line 127

Warning: Cannot modify header information - headers already sent by (output started at /home/hsn/public_html/forum/cache/skin_cache/cacheid_1/skin_topic.php:909) in /home/hsn/public_html/forum/admin/sources/classes/output/formats/html/htmlOutput.php on line 136

Warning: Cannot modify header information - headers already sent by (output started at /home/hsn/public_html/forum/cache/skin_cache/cacheid_1/skin_topic.php:909) in /home/hsn/public_html/forum/admin/sources/classes/output/formats/html/htmlOutput.php on line 137

Warning: Cannot modify header information - headers already sent by (output started at /home/hsn/public_html/forum/cache/skin_cache/cacheid_1/skin_topic.php:909) in /home/hsn/public_html/forum/admin/sources/classes/output/formats/html/htmlOutput.php on line 141
2003 - Multiple Choice - Q2,Q4 - HSN forum

Jump to content


2003 - Multiple Choice - Q2,Q4


16 replies to this topic

#1 jamiep

    Showing Improvement

  • Members
  • PipPip
  • 21 posts
  • Gender:Not Telling

Posted 29 May 2005 - 07:39 PM

Q2) Which of the following convalent gases does not react with water?
A HCl B SO2 C NH3 D CH4

No idea how to get this answer? Is it part of the higher course?

3) An iron nail is covered with water. Which of the following procedures would not increase the rate at which the iron nail corrodes?
A Adding sodium sulphate to the water
B Adding glucose to the water
C Attaching copper wire to the nail
D Passing carbon dioxide through the water

4) Naturally occurring nitrogen consists of two isotopes, 14N and 15N. How many types of nitrogen will occur in the air?

A 1 B 2 C 3 D 4

I can not remember anything about these questions in the course, is it standard grade as I did not do standard grade. Any help would be great.

#2 HatingHighers

    Site Swot

  • Members
  • PipPipPipPip
  • 113 posts

Posted 29 May 2005 - 08:41 PM

Q2) I put D (which was correct as far as I remember), because D is non-polar and all the rest are polar - like water.

Q3) It's Standard Grade. The answer's B because glucose is generally boring and unreactive.

Q4) C. You just go through all the different combinations: 14N-14N 14N-15N 15N-15N

So 2. is applied knowledge, 3. is SG and 4. is problem solving

#3 jamiep

    Showing Improvement

  • Members
  • PipPip
  • 21 posts
  • Gender:Not Telling

Posted 29 May 2005 - 09:47 PM

QUOTE(HatingHighers @ May 29 2005, 08:41 PM)

Q4) C. You just go through all the different combinations:  14N-14N  14N-15N  15N-15N

View Post



Thanks for the help. Can't quite understand the above though, surely the mass number of nitrogen is 14 so it can only either be 14-14N or 15-15N. How could it be 15-15N?

#4 Ally

    HSN Legend

  • Moderators
  • PipPipPipPipPipPipPipPip
  • 2,912 posts
  • Interests:Just finished 1st year at uni studying medicine.
  • Gender:Male

Posted 29 May 2005 - 09:53 PM

QUOTE(jamiep @ May 29 2005, 10:47 PM)
Thanks for the help. Can't quite understand the above though, surely the mass number of nitrogen is 14 so it can only either be 14-14N or 15-15N. How could it be 15-15N?

View Post


It's an isotope.

#5 jamiep

    Showing Improvement

  • Members
  • PipPip
  • 21 posts
  • Gender:Not Telling

Posted 29 May 2005 - 09:57 PM

Sorry i'm just not getting this! sad.gif

#6 bred

    Brendan

  • Moderators
  • PipPipPipPipPipPipPipPip
  • 4,215 posts
  • Location:Edinburgh
  • Interests:I have just graduated with a 2:1 in Geography [MA (Hons)] from The University of Edinburgh. I like sports: swimming, cycling, snowboarding, running, football, mountain biking and also travelling and photography.
  • Gender:Male

Posted 29 May 2005 - 10:10 PM

There are two isotopes of nitrogen - N14 and N15.
Nitrogen is diatomic so one of the two isotopes will always be bonded to another atom (also one or other of the two isotopes).
Therefore, N14-N14 is possible, N14-N15 is possible, and N15-N15 is possible.
Thus, three types.
Please vote for me! (Brendan Howard, 5th from bottom, only 1 vote required): http://answers.polld...m/poll/2330393/

#7 jamiep

    Showing Improvement

  • Members
  • PipPip
  • 21 posts
  • Gender:Not Telling

Posted 29 May 2005 - 10:22 PM

Ahh! Thanks again!! biggrin.gif

#8 jamiep

    Showing Improvement

  • Members
  • PipPip
  • 21 posts
  • Gender:Not Telling

Posted 30 May 2005 - 09:28 AM

Final question I'm not so sure about in 2003 is number 32:

ICl(l) + Cl2(g) <-> ICl3(s) H= -106kJ mol-1


Which line identifies the changes that will cause the greatest increase in the proportion of solid in the above equilibrium?

I thought the answer must be C (Increase in temp, decrease in pressure) but its the opposite, B (decrease in temp, increase in pressure)! ohmy.gif

#9 bred

    Brendan

  • Moderators
  • PipPipPipPipPipPipPipPip
  • 4,215 posts
  • Location:Edinburgh
  • Interests:I have just graduated with a 2:1 in Geography [MA (Hons)] from The University of Edinburgh. I like sports: swimming, cycling, snowboarding, running, football, mountain biking and also travelling and photography.
  • Gender:Male

Posted 30 May 2005 - 09:37 AM

Decrease in temperature favours the exothermic (and in this case forward) reaction and increase in pressure moves equilibrium to side with least pressure (le Chatelier's principle).
Please vote for me! (Brendan Howard, 5th from bottom, only 1 vote required): http://answers.polld...m/poll/2330393/

#10 jamiep

    Showing Improvement

  • Members
  • PipPip
  • 21 posts
  • Gender:Not Telling

Posted 30 May 2005 - 09:53 AM

So equilibrium would be to the right? Would that not mean there will be less solid and more reactants?

#11 bred

    Brendan

  • Moderators
  • PipPipPipPipPipPipPipPip
  • 4,215 posts
  • Location:Edinburgh
  • Interests:I have just graduated with a 2:1 in Geography [MA (Hons)] from The University of Edinburgh. I like sports: swimming, cycling, snowboarding, running, football, mountain biking and also travelling and photography.
  • Gender:Male

Posted 30 May 2005 - 10:09 AM

Equilibrium moving to the right means more of whatever is on the right will be produced, no?
Please vote for me! (Brendan Howard, 5th from bottom, only 1 vote required): http://answers.polld...m/poll/2330393/

#12 jamiep

    Showing Improvement

  • Members
  • PipPip
  • 21 posts
  • Gender:Not Telling

Posted 30 May 2005 - 10:27 AM

Ok. Think i'm slightly mixed up!

#13 dfx

    Fully Fledged Genius

  • Members
  • PipPipPipPipPipPipPip
  • 1,955 posts
  • Gender:Male

Posted 30 May 2005 - 02:44 PM

Chemists are st00pid idiots who never bothered to look up the dictionary. Although instinctively if the equilibrium moves to the right it would mean more REACTANT is produced, (DUH - LOGICALLY) apparently this is NOT the case. In chemistry if it says the equilibrium moved to the right, more of the stuff on the right is produced. I know. $%^£$%"£%£" mad.gif

#14 gary

    Child Prodigy

  • Members
  • PipPipPipPipPipPip
  • 546 posts

Posted 30 May 2005 - 02:46 PM

The answer to these questions are always:

low temperature, high pressure

I stressed myself out trying to understand it but there is no point that will always be the answer so just know

low temperature, high pressure


#15 dfx

    Fully Fledged Genius

  • Members
  • PipPipPipPipPipPipPip
  • 1,955 posts
  • Gender:Male

Posted 30 May 2005 - 02:50 PM

^ Not necesarily! If an endothermic equation comes up its high temperature, and low pressure if there's more gaseous moles on the right hand side (products) than the left hand side (reactants).

#16 Ally

    HSN Legend

  • Moderators
  • PipPipPipPipPipPipPipPip
  • 2,912 posts
  • Interests:Just finished 1st year at uni studying medicine.
  • Gender:Male

Posted 30 May 2005 - 03:00 PM

QUOTE(gary @ May 30 2005, 03:46 PM)
The answer to these questions are always:

low temperature, high pressure

I stressed myself out trying to understand it but there is no point that will always be the answer so just know

low temperature, high pressure

View Post

ohmy.gif

No it isn't!

It depends on the sign of delta.gifH.

If delta.gifH is -ve for a forward reaction then high temp would favour the back reaction.

If delta.gifH is +ve for the forward reaction, then high temp would favour the forward reaction.


#17 dfx

    Fully Fledged Genius

  • Members
  • PipPipPipPipPipPipPip
  • 1,955 posts
  • Gender:Male

Posted 30 May 2005 - 03:07 PM

Precisely, its real easy once you get the hang of it - which is quite straightforward.. if you need any help just post smile.gif





1 user(s) are reading this topic

0 members, 1 guests, 0 anonymous users