Posted by haynesycop
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[ This Message was edited by: miss copperfield on 2006-06-16 19:09 ]
Posted by frank2345babies
I know some chemistry. Post ur questions and i will try 2 help.
Posted by Glenny
it depends what sort of chemistry,i got a B in it (well im AT a B) so if its GCSE level i COULD help, not too sure, depends...
Posted by lamont
im at A* at GCSE if you need some help
Posted by haynesycop
Thanks guys! It is access level which is A Level equivalent i suppose, will get the questions up asap. Just got an essay to finish.
Cheers for this in advance. You will probably think i am thick
Posted by BOOYAR
Gcse A*Alevel A Biochemistry degree and currently studying pHD in biochemistry, I'll do my best
Posted by haynesycop
Ok here they are:
1) Balance the following equations:
BaCl2 + Na2SO4 gives NaCl + BaSO4
C5H11OH + O2 gives CO2 + H2O
2) The molar mass of potassium carbonate, K2CO3, is 138.
a) Determine the percentage of potassium and carbonate ions in K2CO3
b) When potassium carbonate was added to an aqeuous solution containing 10g of silver nitrate a precipitate of silver carbonate was produced.
i) Calculate the moles of AgNO3 in 10g.
ii) Hence determine the moles of Ag2CO3 produced by the 10g of AgNO3
iii) Calculate the mass of Ag2CO3 produced.
iv) What mass of K2CO3 is needed to react with 10g of AgNO3
c) Analysis of the essencial amino acid asparagine showed that it contains 41 36% carbon, 8.06% hydrogen, 32.19% nitrogen and 18.38% oxygen. It has a relative molecular mass of 174. Determine the molecular formula of asparagine.
Ok so i am not sure how to get the numbers to shop up small but they won't but i am sure you know what i mean, very grateful to anyone that can help out, i just do not get all of these calculations stuff.
Posted by fatreg
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surely the dide that wrote the questions knows the answers, so what is the point in you answering??
just realised thats about as helpful as a chocolate fireguard, sorry ill leave now.
fatreg
Posted by EastCoastStar
i dont have time right now, but if you still need it, i can gladly do it later. (not too hard
, i was alwyas good at chemistry and math)
Posted by rrojas260
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I gtg now, that is 9th grade chemestry so they are very easy. I will try to finishing answering later.
Posted by Glenny
yup very easy. From what i know, all i can make of it is you will have to give a number infront of the molecule, e.g (not real) CO2 + H20 = 6C12H20 there would be a 6 infront of C and a 12 infront of H? i cant remember it all too well, im crap at biology now i look at it...
Posted by Uncle Bob
Thought I had it - nevermind...
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[ This Message was edited by: Uncle Bob on 2006-02-07 23:24 ]
Posted by haynesycop
So can anyone help i just don't get it at all it is supposed to be pretty easy but i have always been crap at it got to be done by friday
Posted by methylated_spirit
Arnold Schwarzenegger destroyed the periodic table, because Arnold Schwarzenegger only recognizes the element of surprise.
(sorry)
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[ This Message was edited by: methylated_spirit on 2006-02-08 09:36 ]
Posted by Luke-the-magic-man
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ha ha, that made me laugh mate.
Il ask my gf if I see her tonight shes on a2 chemistry I think, aka year 13
Posted by clank
Ans 1) BaCl2 + Na2SO4 gives 2(NaCl) + BaSO4
2(C5H11OH) + 15(O2) gives 10(CO2) + 12(H2O)
Ans 2) % of K+ ions = (mass of K)/total mass = 78/138 = 56.52%
Similarly % of CO3 ion = 60/138 = 43.48%
moles of AgNO3 = 10/mol. mass of AgNO3 = 10/170 = 0.059
if you balance the eq you'll see one mole of AgNO3 gives 0.5 moles of Ag2CO3 so 0.059 will give 0.029 moles of Ag2CO3 weighing
0.029x276 = 8.0g
to react with 10g ie 0.059 moles of AgNO3 you need 0.029 moles of K2CO3 ie 0.029x138 = 4g
Ans 3) C3H7N2O The solution is slightly understanding based and i dont think i'll be able to explain it in writing so i'm just printing the answer.
Hope that helps
Posted by haynesycop
Wow thanks mate that is great! I am just thick were chemistry is concerned!
THANK YOU!!!!!!
If i can ever return the favour then let me know.
Posted by fatreg
So...
Miss C,
can you please expalin your working out?
they got me with that everytime at school
fatreg
Posted by Kwiksta
oh! we're doing this at the moment in school...ill try 2 help!
Posted by haynesycop
Ok so is anybody up for some more questions, the book i use to help me has disappeared from the college library, it is like my chemistry bible, not happy.
I got one question were i have to work out a pka and i was off for that lesson, so totally clueless.
Posted by govigov
post away....
Posted by haynesycop
Hey i wll do later a soon as i get back from college this afternon, really appreciate this.
Posted by methylated_spirit
you big lazy cheater! You should be hounded out of Esato, and college! In my day...
Posted by haynesycop
It is not like they are homework as such there just practice questions for the real thing if i can make sure i can get the right answers for these then i can apply the working out to everything else.
Really need to get the hang of chemistry i have never done any in school apart from a few stupid experiments never done calculations before and the teacher doesn't explain things very well.
Posted by haynesycop
ARG!!! I have had alot of questions to do in chemistry, around 25 and i have managed to do all of them, by some miracle, apart from these, don't suppose anyone could help me out?
1. The rate equation for a reaction A + B ? products was found, by experiment, to be:
Rate = 0.26 x [A]x[B]2
A) State the order of reaction with respect to A and to B. What is the overall order for the reaction?
B) What would be the increase in rate if the concentrations of both A and B were doubled at the same time? I THINK THIS IS TIMES BUT I HAVE NO IDEA WHY?
C) Calculate the expected reaction rate if [A] = 0.16 mol dm-3 and [B] = 0.32 mol dm-3
2. An acid buffer solution is an aqueous solution of a weak acid (HA) and it’s sodium salt (NaA)
I) Explain why there is only a small pH change when a small volume of acid is added to this buffer solution.
II) Given that the pKa value of HA is 4.35, what will be the pH of a buffer solution that contains 0.35 moles of NaA and 0.25 moles of HA?
3. Give the chemical formulae of the products formed when ethane (CH2=CH2) and propene (CH3CH=CH2) react with each of the following:
A) H2 with Ni catalyst
B) Bromine Br2
C) Hydrogen bromide, HBr
D) What product forms when the products of reactions B and C react with aqueous sodium hydroxide, NaOH?
4. Two alcohols are CH3CH2CH2OH and (CH3)2CHOH (propan-1-ol and propan-2-ol)
Give the formula of the products formed when each alcohol reacts
with ethanoic acid (CH3COOH). To what class of organic compound
Do these products belong?
What are the oxidation products of these alcohols? Explain how the oxidation products could be used to distinguish between these alcohols by means of a chemical test.
Would really appreciate it, this is the last thing ever for chemistry then it is over, thank god!
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[ This Message was edited by: miss copperfield on 2006-05-22 09:37 ]
[ This Message was edited by: miss copperfield on 2006-05-22 09:38 ]
Posted by clank
1.
A) 1 and 2 resp. total order 3
B) 8
C) Substitute values
2.
A) Thats what a buffer is suppposed to be. Adding of H+ will shift equilibrium backwards and the H+ will be consumed hence little ph change.
B)pH = pKa + log(moles of NaA/moles of HA) Put values and solve
3.
A) syn addition of 2 H across the double bond
B) anti addition of 2 Br across the double bond
C) CH3-CH2Br and CH3CHBr-CH3
D) replace Br groups with OH
4.
CH3CH2CH2OCOCH3 and (CH3)2CHOCOCH3. Both Esters
On oxidation Acid and Ketone resp. Do any test for acids to distinguish eg do sodalime decarboxylation and test for CO2 with lime-water.
I'm really sleepy at the moment so sorry if there are any errors as i'm trying to rush through this...
Posted by haynesycop
Oh clank i love you, thank you so much you are a genius!!!
Much much much much appreciated!!!
Thanks!!!
Posted by haynesycop
I'm Back!
Ok so i have two assignments due on tuesday before i finish my course and i have near enough finished one but i cannot find the answers to the following;
1.
The chlorides of sodium and phosphorus are Na2O, NaCl, P4O10 and PCl3, state what bonding is present in each compound?
2.
Classify the oxides as either acidic or basic and give equations that show what happens when they are added to water?
3.
Give equations that show what happens when NaCl and PCl3 are added to water?
I can find various bits and bobs through google but nothing conclusive, can anybody recommend a decent chemistry site all the ones i have find are very clogged with loads of information.
I am also stuck on a few other things if anybody can help me out then pop me a pm, god i hate this subject why the hell i choose it i will never know.
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[ This Message was edited by: miss copperfield on 2006-06-16 19:18 ]