Just a reminder that our test will be in tomorrow's lesson, with questions on:
- Oxidation numbers and redox
- Intermolecular forces
- Group 7
- Group 2
You can find some revision resources at the following link, which I hope you will find useful.
http://cedarschemistry.edublogs.org/revision-resources-dec-2008/
See you on Monday!
Sunday, 14 December 2008
Saturday, 13 December 2008
Increasing reactivity of group 2
The reactivity of of group 2 increases as you go down, and the first ionisation energy decreases down to Barium, because of the increased atomic size and more shielding. However, the first ionisation energy of radium is slightly higher than barium, 509 kJ/mol compared to 502. Is this because the nucleus of radium is so much larger so counteracts the effect of another full shell of electrons?
Also, what chemical and physical properties of Group 2 do we have to know?
Also, what chemical and physical properties of Group 2 do we have to know?
Wednesday, 3 December 2008
Mr Beaumont sheet
On the sheet Mr Beaumont gave us, Q13 is
Cr2O7 2- + 14 H+ + 6 e- ---> 2Cr3+ + 7H2O
Fe2+ ----> Fe3+ + e-
60 cm3 of acidified dichromate (VI) solution with a concentration of 0.05 mol/dm3 was titrated against a 0.6 mole/dm3 Fe 2+ solution. What volume of Fe 2+ solution would be required to reach the end point of this titration?
I don't understand how the equations above help you to work out what happens in the titration except for the fact you can see what the ions of each substance are...
Thanks.
Cr2O7 2- + 14 H+ + 6 e- ---> 2Cr3+ + 7H2O
Fe2+ ----> Fe3+ + e-
60 cm3 of acidified dichromate (VI) solution with a concentration of 0.05 mol/dm3 was titrated against a 0.6 mole/dm3 Fe 2+ solution. What volume of Fe 2+ solution would be required to reach the end point of this titration?
I don't understand how the equations above help you to work out what happens in the titration except for the fact you can see what the ions of each substance are...
Thanks.
Tuesday, 2 December 2008
halogens
halogens decrease in reactivity down the group, because their ability to gain electrons decreases because:
the atomic radi increases
the electron shielding increases
...
how excactly do these two factors affect its oxidising ability? is it because the electrostatic attraction between the electrons they may gain has decreased because of these two factors, or something completely different?
the atomic radi increases
the electron shielding increases
...
how excactly do these two factors affect its oxidising ability? is it because the electrostatic attraction between the electrons they may gain has decreased because of these two factors, or something completely different?
Monday, 1 December 2008
Work for Mrs Sudbery's group - 1st December
Sorry not to be in our lesson today but I hope to be back in by Wednesday. You should have been provided with work for the lesson but if not, please download it by following the link below and right-clicking on the document names.
http://cedarschemistry.edublogs.org/group-7-resources/
http://cedarschemistry.edublogs.org/group-7-resources/
Wednesday, 19 November 2008
Mrs Sudbery's group - Work set on 19th November
As discussed in today's lesson, please follow the link below to download the 'Halogens' presentation and the tick list for the next topic which is all about Group 7.
http://cedarschemistry.edublogs.org/work-set-on-19th-november/
Please use the tick list as a guide to the learning points that we will be covering over the next 2 weeks and work through the presentation, making your own neat notes and completing the tasks on each slide.
Please see me by Friday if you are having any trouble accessing the resources and aim to bring your completed work to next Wednesday's lesson.
Also, remember that your blue 'Homework 3 - Redox' sheet is due in on Wednesday too.
See you next week!
http://cedarschemistry.edublogs.org/work-set-on-19th-november/
Please use the tick list as a guide to the learning points that we will be covering over the next 2 weeks and work through the presentation, making your own neat notes and completing the tasks on each slide.
Please see me by Friday if you are having any trouble accessing the resources and aim to bring your completed work to next Wednesday's lesson.
Also, remember that your blue 'Homework 3 - Redox' sheet is due in on Wednesday too.
See you next week!
Sunday, 9 November 2008
Mr. Beaumont's Booklet again....
Question 3 "what volume of 0.500M sodium hydroxide is needed to neutralise 22.5cm^3 of a solution of 0.262M sulphuric acid?" of task 1.2f is confusing me.
I've worked out they react in a 2:1 ratio but without the concentration of sodium hydroxide I am unable to find the volume. the answer given is 23.6cm^3 but I have no idea how that answer camt to be.
can someone help please?
I've worked out they react in a 2:1 ratio but without the concentration of sodium hydroxide I am unable to find the volume. the answer given is 23.6cm^3 but I have no idea how that answer camt to be.
can someone help please?
Friday, 7 November 2008
Another Website...
This afternoon in physics Dr Miller told us of a website that has loads of videos about the elements done by Nottingham University. We watched a couple and they were really good.
www.periodicvideos.com
www.periodicvideos.com
Sunday, 2 November 2008
Best Choice
Now you have all had a little break It is time to get back to work.
Visit the Best Choice website
http://130.216.56.150/bclogin.aspx?ReturnUrl=%2fDefault.aspx
and log in/register as a new user and then enrol in your class.
Now when you do any activities we can see how much you do and how you are getting on.
At present classes are only available for year 12, year 13 coming soon.
Have fun. Mrs B
Visit the Best Choice website
http://130.216.56.150/bclogin.aspx?ReturnUrl=%2fDefault.aspx
and log in/register as a new user and then enrol in your class.
Now when you do any activities we can see how much you do and how you are getting on.
At present classes are only available for year 12, year 13 coming soon.
Have fun. Mrs B
Tuesday, 21 October 2008
Mr Beaumont booklet on moles
Task 1.2c (second sheet)
Question 3
What mass of glucose can be fermented to give 5.00g of ethanol?
C6H12O6 (aq) ---> 2C2H5OH (aq) + 2CO2 (g)
I thought I knew how to do this sort of question, but I got a different answer from the one on the sheet, and can't work out where I went wrong.
This is what I did:
Relative molecular mass of ethanol = 24 + 5 + 16 + 1 = 46
Moles of ethanol = mass/relative molecular mass = 5/46 = 0.109 mol
Moles of glucose = 1/2 * moles of ethanol = 1/2 * 0.109 = 0.0543 mol
Relative molecular mass of glucose = (6 * 12) + 12 + (6 *16) = 180
Mass of glucose = moles * relative formula mass = 180 * 0.0543 = 9.78g
The final answer on the sheet is 8.91g.
Thanks.
Question 3
What mass of glucose can be fermented to give 5.00g of ethanol?
C6H12O6 (aq) ---> 2C2H5OH (aq) + 2CO2 (g)
I thought I knew how to do this sort of question, but I got a different answer from the one on the sheet, and can't work out where I went wrong.
This is what I did:
Relative molecular mass of ethanol = 24 + 5 + 16 + 1 = 46
Moles of ethanol = mass/relative molecular mass = 5/46 = 0.109 mol
Moles of glucose = 1/2 * moles of ethanol = 1/2 * 0.109 = 0.0543 mol
Relative molecular mass of glucose = (6 * 12) + 12 + (6 *16) = 180
Mass of glucose = moles * relative formula mass = 180 * 0.0543 = 9.78g
The final answer on the sheet is 8.91g.
Thanks.
Monday, 20 October 2008
Titrations Green Question Paper
Question 5
On the answers it says you multiply the moles of IO3(-), which is 2.3 x 10^-3, by the molar mass of iodine. Isn't it I2, and so you would multiply by not 127, but 127 x 2?
Is it because the iodine is involved in a compound and so we use simply the molar mass of I, not I2??
On the answers it says you multiply the moles of IO3(-), which is 2.3 x 10^-3, by the molar mass of iodine. Isn't it I2, and so you would multiply by not 127, but 127 x 2?
Is it because the iodine is involved in a compound and so we use simply the molar mass of I, not I2??
Simple Molecular Structures Solubility
They are soluble in non-polar solvents because van der waal's forces form between the simple structure & the solvent, which allows a solution to form.
But are they soluble in polar solvents?
If not, why not, if yes, why?
cheers
But are they soluble in polar solvents?
If not, why not, if yes, why?
cheers
Monday, 13 October 2008
Ionic Equation?
What is an ionic equation?
(Practice Exam Q's on titrations, Question 4)
It says 'sodium thiosulphate' but there's no 'Na' in the equation!!
(Practice Exam Q's on titrations, Question 4)
It says 'sodium thiosulphate' but there's no 'Na' in the equation!!
Sunday, 12 October 2008
Monday 13th
Is mrs Sudbery going to be in on monday, for some reason i didnt think she was.
But anywho, if she isnt in then are we still going to be doin the presentations, whos doing it, and what is it about ? just so i can get some backgroung knowlage.
thanks evreyone.
mikey
p.s did anyone else actually do the green sheets in the time limit (1point=1min), on every one i was out by about 5 mins. is that the actual amout of time we get in the exam, because if so, them methinks i need more practice.
But anywho, if she isnt in then are we still going to be doin the presentations, whos doing it, and what is it about ? just so i can get some backgroung knowlage.
thanks evreyone.
mikey
p.s did anyone else actually do the green sheets in the time limit (1point=1min), on every one i was out by about 5 mins. is that the actual amout of time we get in the exam, because if so, them methinks i need more practice.
RSC Online Chemistry 'Check-up'
Just a reminder that there's just one week left for you to take the Royal Society of Chemistry's online Chemistry 'check-up'. It's aimed at students like you, who have just started doing AS Chemistry and the deadline is 19th October.
The website link is: http://www.rsc.org/education/teachers/learnnet/olympiad_l6checkup.htm
It consists of 40 multiple choice questions of varying difficulty which test knowledge and understanding of some of the important fundamental topics in chemistry. The test can be taken several times by the same student and there is no time limit for each attempt. At the end of the test, students receive individual feedback (by email) on their performance - broken down into the main areas of chemistry. This is intended to help improve understanding and learning. Teachers will receive this feedback directly if their email address is entered when prompted.
The website link is: http://www.rsc.org/education/teachers/learnnet/olympiad_l6checkup.htm
It consists of 40 multiple choice questions of varying difficulty which test knowledge and understanding of some of the important fundamental topics in chemistry. The test can be taken several times by the same student and there is no time limit for each attempt. At the end of the test, students receive individual feedback (by email) on their performance - broken down into the main areas of chemistry. This is intended to help improve understanding and learning. Teachers will receive this feedback directly if their email address is entered when prompted.
Friday, 10 October 2008
Orbitals
In Mr Beaumont's lesson we were doing orbitals. He showed us how P orbitals and how they go in X, Y and Z directions, but how do the electrons actually go around in them because they cannot go to the origin like the diagram showed because isn't that where the nucleus is? I am confused about it.
Thursday, 9 October 2008
electron pairs
i was trying to think of why there are electron pairs.
is the reason: that sub shells have electrons in pairs, and so this is why the electrons are in pairs.
what happens if there are 3 electrons in the outer shell spare? there will be one pair and then one lone electron? what happens with the repulsion there?
and then there area bonded electron and a lone electron pair, how does that happen?
is the reason: that sub shells have electrons in pairs, and so this is why the electrons are in pairs.
what happens if there are 3 electrons in the outer shell spare? there will be one pair and then one lone electron? what happens with the repulsion there?
and then there area bonded electron and a lone electron pair, how does that happen?
Shapes of Molecules
in my notes it says that we count the number of electron pairs to see what the shape of molecule is classed as.
e.g. H2O would actually be classed as tetrahedral, as it has two lone pairs and two bonded pairs.
In the book it says that H2O is actually classed as non-linear.
I have guessed that the shape of molecule is possibly classed by the amount of bonded pairs? not the amount of pairs overall?
also i have presumed that if it has four bonded pairs, the angle will be 109.5
But then if it has three bonded pairs, and then one lone pair, the new angle would then become 107.5 . . . . .
e.g. H2O would actually be classed as tetrahedral, as it has two lone pairs and two bonded pairs.
In the book it says that H2O is actually classed as non-linear.
I have guessed that the shape of molecule is possibly classed by the amount of bonded pairs? not the amount of pairs overall?
also i have presumed that if it has four bonded pairs, the angle will be 109.5
But then if it has three bonded pairs, and then one lone pair, the new angle would then become 107.5 . . . . .
Wednesday, 8 October 2008
Pink support sheets
On the last page of the pink booklet (mole calculations)
Question 3a is How many moles of hydrogen in every mole of HCl?
What does this mean? Because surely it's a compound so to work out moles of hyrdogen is meaningless. Am I missing something here?
Thanks.
Question 3a is How many moles of hydrogen in every mole of HCl?
What does this mean? Because surely it's a compound so to work out moles of hyrdogen is meaningless. Am I missing something here?
Thanks.
Sunday, 5 October 2008
Intermolecular forces presentation
Hi
We're working on our intermolecular forces presentation but have some questions as follows:
Why does boiling point decrease going down Group 0?
When talking about dipoles, do we have to explain why they exist with reference to core charge?
Do we have to cover hydrogen bonding or the covalent character of ionic bond?
How do you pronounce van der waals and delta.
Apart from that, we're fine!
See you on Monday.
jo
x
We're working on our intermolecular forces presentation but have some questions as follows:
Why does boiling point decrease going down Group 0?
When talking about dipoles, do we have to explain why they exist with reference to core charge?
Do we have to cover hydrogen bonding or the covalent character of ionic bond?
How do you pronounce van der waals and delta.
Apart from that, we're fine!
See you on Monday.
jo
x
Friday, 3 October 2008
Catching up...
Just to check, what should I know, so that if I have forgotten to do anything i still have this weekend to do it?
Wednesday, 1 October 2008
Bita moles
In beaumonts lesson we did the find the relative atomic mass of an unkown metal by gas collection.
x (unkown metal) = 0.20 g
1MHCL we used 25cm3
Volume of hydrogen gas we found out was 192 cm3 (in my experiment).
Equation was : x + 2HCl = xCl2 + H2
We were told to find the relative atomic mass of x, which I found was 25 (in my experiment)
On the sheet for the experiment that we were given, one question is "Calculate amounts in moles (using your value Ar for x) to show that the acid was in excess".
any ideas on this one? when i converted moles of HCl (which i found by multiplying moles of x by two) to volume (v=24000n) i found it was way greater than the 25cm3 we used. how do i do it:S?
x (unkown metal) = 0.20 g
1MHCL we used 25cm3
Volume of hydrogen gas we found out was 192 cm3 (in my experiment).
Equation was : x + 2HCl = xCl2 + H2
We were told to find the relative atomic mass of x, which I found was 25 (in my experiment)
On the sheet for the experiment that we were given, one question is "Calculate amounts in moles (using your value Ar for x) to show that the acid was in excess".
any ideas on this one? when i converted moles of HCl (which i found by multiplying moles of x by two) to volume (v=24000n) i found it was way greater than the 25cm3 we used. how do i do it:S?
Tuesday, 30 September 2008
Welcome to our Chemistry blog!
Dear Year 12 chemists,
Welcome to our blog! The purpose of this is to provide you with an additional means of support with your work in Chemistry this year. As the terms goes on, I will add resources to this page so that you can access homework sheets and such from home - especially useful if you can't make it to the lesson for any reason!
In the meantime, please feel free to comment on my post or to start a post of your own, for example to add suggestions about what you would like to see on the blog (all chemistry-related ideas gratefully received!). You could also use it to ask me (or each other) questions about the work if you're stuck or even to extend your understanding further, especially when you're working late at night or at the weekend and need some help!
Just one other thing... Please take part in the poll to the righthandside of this post and let me know how you're finding Chemistry so far - you can tick more than one box if relevant. It's anonymous so please do be honest about how you're getting on and keep checking the blog to see if everyone else feels the same or not!
Anyway.... happy blogging and I look forward to reading your posts!
Welcome to our blog! The purpose of this is to provide you with an additional means of support with your work in Chemistry this year. As the terms goes on, I will add resources to this page so that you can access homework sheets and such from home - especially useful if you can't make it to the lesson for any reason!
In the meantime, please feel free to comment on my post or to start a post of your own, for example to add suggestions about what you would like to see on the blog (all chemistry-related ideas gratefully received!). You could also use it to ask me (or each other) questions about the work if you're stuck or even to extend your understanding further, especially when you're working late at night or at the weekend and need some help!
Just one other thing... Please take part in the poll to the righthandside of this post and let me know how you're finding Chemistry so far - you can tick more than one box if relevant. It's anonymous so please do be honest about how you're getting on and keep checking the blog to see if everyone else feels the same or not!
Anyway.... happy blogging and I look forward to reading your posts!
Subscribe to:
Posts (Atom)