Tonnes of problem in P5 Chemistry ! Please help me b4 exam!!

[Youme&I]

I need help paper 5 chemistry 9701

Nov10/53 question 2(a) , how to find the concentration of the succinic acid in each layer by the given data in the table???

June 07 question 1(d) , can anybody show or explain me what are the proper ways to design the laboratory experiment.

Which must include all the steps given from (i) to (vi).

Your plan should give a step-by-step description of the method, including
(i) a list of the apparatus you would use,
(ii) how you would measure the independent variable and how you would ensure that
its value has been measured accurately,
(iii) how you would mix the reactants without loss of gas from the apparatus,
(iv) how you would measure the dependent variable,
(v) how you would control the other variables,

(vi) appropriate quantities (volumes, relative concentrations) to use in the experiment.

 

[xarak]

Re: Tonnes of problem in P5 Chemistry ! Please help me b4 ex

For nov 10
in succinic acid there are 2 hydrogen atoms to react with the NaOh just as in the case of H2SO4.This is a weak acid as its organic.There wud b a 1:2 ratio between number of moles of NaOH and succinc acid respectively.
now to calculate the values of column D:
calculate number of moles of NaOH ie C=n/V therefore 0.1x(value in column B/1000)=n
since NaOH:succinic acid is 1:2 ratio so to calculate number of moles of succinic acid divide by 2
calculate concentration by C=n/V number of moles ^^/(10/1000) 10 cm3 because thts the volume of water layer

repeat the same steps for column E but take concentration of NaOH 0.02 nd in concentration of succinic acid volume shud be taken as 25cm3

I hope tht helped..i kinda suck in given explainations

 

[xarak]

Re: Tonnes of problem in P5 Chemistry ! Please help me b4 ex

In a conical flask add 2g of a magnesium ribbon and add a rubber bung.Connect a 100 cm3 graduated syringe through the rubber bung by using a delivery tube and connect a burette as well through it.
Next,wash a volumetric flask with distilled water and dry it.Using a burette measure 125cm3 of HCl of the 2 mol/dm3 given and measure 125cm3 of distilled water and add in the flask to make up a volume of 250cm3.Stop the mouth of the flask with your thumb and invert several times to obtain a uniformly diluted solution of half the concentration ie 1 mol/dm3.Prepare 5 more solutions of different concentrations.The volume of HCl added each time can b caluclated by the formula : Volume of Hcl to be added= [Concentration required/Concentration given]xTotal volume of solution u have to make ie 250cm3.
The independent variable is the concentration of HCl which can be measured accurately by measurin an accurate volume of HCl from the burette.
Using the burette add 50cm3 of HCl(you cant take any volume you want)and measure the Hydrogen gas collected for a known duration of time.Record the volume of H2 produced from the graduated syringe.Repeat the experiment with diferent concentrations.The variables to be kept constant are mass and size of the magnesium ribbon.2g mass has to measured each time usin a weighin balance.The volume of Hcl added should be constant (50cm3) each timethe temperature should also be kept constant.
Calculate the volume of H2 formed by takin the concentration of HCl say 0.2 mol/dm3
Calculation:
C=n/V 0.2x0.05= number of moles of HCl
0.01
from the equation HCl:H2 ratio is 2:1 therefore number of moles of H2 are 0.01/2=5x10^-3
Volume of Co2=nx24 therefore 5x10^-3 x 24=0.12 dm3
thts all i hope tht helps ^_^

 

[Youme&I]

Re: Tonnes of problem in P5 Chemistry ! Please help me b4 ex

In a conical flask add 2g of a magnesium ribbon and add a rubber bung.Connect a 100 cm3 graduated syringe through the rubber bung by using a delivery tube and connect a burette as well through it.
Next,wash a volumetric flask with distilled water and dry it.Using a burette measure 125cm3 of HCl of the 2 mol/dm3 given and measure 125cm3 of distilled water and add in the flask to make up a volume of 250cm3.Stop the mouth of the flask with your thumb and invert several times to obtain a uniformly diluted solution of half the concentration ie 1 mol/dm3.Prepare 5 more solutions of different concentrations.The volume of HCl added each time can b caluclated by the formula : Volume of Hcl to be added= [Concentration required/Concentration given]xTotal volume of solution u have to make ie 250cm3.
The independent variable is the concentration of HCl which can be measured accurately by measurin an accurate volume of HCl from the burette.
Using the burette add 50cm3 of HCl(you cant take any volume you want)and measure the Hydrogen gas collected for a known duration of time.Record the volume of H2 produced from the graduated syringe.Repeat the experiment with diferent concentrations.The variables to be kept constant are mass and size of the magnesium ribbon.2g mass has to measured each time usin a weighin balance.The volume of Hcl added should be constant (50cm3) each timethe temperature should also be kept constant.
Calculate the volume of H2 formed by takin the concentration of HCl say 0.2 mol/dm3
Calculation:
C=n/V 0.2x0.05= number of moles of HCl
0.01
from the equation HCl:H2 ratio is 2:1 therefore number of moles of H2 are 0.01/2=5x10^-3
Volume of Co2=nx24 therefore 5x10^-3 x 24=0.12 dm3
thts all i hope tht helps ^_^

Thankz Xarak ! You are the best! ThannkSSS ! I havent look onto the paper 5 questions for a while now after I have difficulties on the questions I posted. In a few minutes I will try to do again with your guidelines hopefully I will understand easily. I will look for you Xarak if I still have difficulties on paper 5 questions again . I will pm you my hotmail and yahoo address to make it easier for us.

 

[Youme&I]

Re: Tonnes of problem in P5 Chemistry ! Please help me b4 ex

For nov 10
in succinic acid there are 2 hydrogen atoms to react with the NaOh just as in the case of H2SO4.This is a weak acid as its organic.There wud b a 1:2 ratio between number of moles of NaOH and succinc acid respectively.
now to calculate the values of column D:
calculate number of moles of NaOH ie C=n/V therefore 0.1x(value in column B/1000)=n
since NaOH:succinic acid is 1:2 ratio so to calculate number of moles of succinic acid divide by 2
calculate concentration by C=n/V number of moles ^^/(10/1000) 10 cm3 because thts the volume of water layer

repeat the same steps for column E but take concentration of NaOH 0.02 nd in concentration of succinic acid volume shud be taken as 25cm3

I hope tht helped..i kinda suck in given explainations

I try to do the question back again, however I dont understand how is it to calculate number of moles of succinic acid divide by 2? isn't it suppose to be times 2 ? since 1:2 ,

as Expt 1 as an example:
no of mols of NAOH = 2.43x10^-3 so to find no of mols of Succinic acid= 2 x 2.43x10^-3 right? or I m wrong. Please correct me ..

 

[xarak]

Re: Tonnes of problem in P5 Chemistry ! Please help me b4 ex

Your welcome haha yeah i have dumped chem for a while too for physics =/ buh gudluck to u oh nd bout the email address..hm..i kinda have a shared account so can i noe ur name LOL [dont mind tht plz ]
Oh nd yeahhh i guess ur rite bout the x2 part..it wux my chem sir who made me solve this question nd i wux half asleep so dint notice.oh well ive a class tommorow ill ask him nd let u noe ok

 

[WellWIshER]

Re: Tonnes of problem in P5 Chemistry ! Please help me b4 ex

can some one please xplain june 07 q2???

y do we find da gradient????

 

[workinghard]

Re: Tonnes of problem in P5 Chemistry ! Please help me b4 ex

oh k it depends on da graf u made!
wat did u made ur graf against?
it ll show u da ratios of Hg and Cl ions in an HgClx
or atleast is supposed 2!

 

[WellWIshER]

Re: Tonnes of problem in P5 Chemistry ! Please help me b4 ex

y do we find da ratio?

 

[workinghard]

Re: Tonnes of problem in P5 Chemistry ! Please help me b4 ex

well u do want da value of x dont u?
sory! just teasin!
the ratio ll b the reactin ratio of Hg and Cl as in how many moles of Hg ll react with Cl and rounding up the ratio will give u the calue of both elements in da compound!

 

[WellWIshER]

Re: Tonnes of problem in P5 Chemistry ! Please help me b4 ex

can u solve it?

 

[Youme&I]

Re: Tonnes of problem in P5 Chemistry ! Please help me b4 ex

Your welcome haha yeah i have dumped chem for a while too for physics =/ buh gudluck to u oh nd bout the email address..hm..i kinda have a shared account so can i noe ur name LOL [dont mind tht plz ]
Oh nd yeahhh i guess ur rite bout the x2 part..it wux my chem sir who made me solve this question nd i wux half asleep so dint notice.oh well ive a class tommorow ill ask him nd let u noe ok

Aww too bad! would like to chat with you to know more on chemistry. Since I dropped physic hahaa.. and start loving chemistry now!

Hope you will add me in one of the email I send to you. Because I m sure I will have tonnes of problem when I do different question papers.

 

[WellWIshER]

Re: Tonnes of problem in P5 Chemistry ! Please help me b4 ex

anyone????

 

[WellWIshER]

Re: Tonnes of problem in P5 Chemistry ! Please help me b4 ex

is tht da ans???

 

[princesszahra]

Re: Tonnes of problem in P5 Chemistry ! Please help me b4 ex

is tht da ans???

what type of answer is that??i mean is this english of french???

 

[WellWIshER]

Re: Tonnes of problem in P5 Chemistry ! Please help me b4 ex

no idea

can some tell me why and how to find find da ratio!!!!!

to get x??

 

[xarak]

Re: Tonnes of problem in P5 Chemistry ! Please help me b4 ex

Your welcome haha yeah i have dumped chem for a while too for physics =/ buh gudluck to u oh nd bout the email address..hm..i kinda have a shared account so can i noe ur name LOL [dont mind tht plz ]
Oh nd yeahhh i guess ur rite bout the x2 part..it wux my chem sir who made me solve this question nd i wux half asleep so dint notice.oh well ive a class tommorow ill ask him nd let u noe ok

Aww too bad! would like to chat with you to know more on chemistry. Since I dropped physic hahaa.. and start loving chemistry now!

Hope you will add me in one of the email I send to you. Because I m sure I will have tonnes of problem when I do different question papers.

haha loving chem?hardd to do my frnd..yeh i will, name plz?

 

[sakaria john]

tyga