Chem P5 most common planning questions and topics

[WellWIshER]

they say STRAIGHT LINES!!

HOW R WE SUPPOSE TO KNOW THT A CURIVE IS INVOLVED!!!!

 

[Youme&I]

Wow.... tats a lot. paper 5 is a few days ahead and surely need helps in this question! hellpp me guys!!! before its too late!

Hey guys! I m still not sure about paper 5 chemistry, for example a question from Nov10/53 question 1

Using the apparatus shown in (c) design a laboratory experiment to test your prediction
in (a). In addition to the standard apparatus present in a laboratory you are provided with the
following materials.

• 2.00 mol dm–3 aqueous hydrogen peroxide
• a supply of manganese(IV) oxide
(i) Complete the table below to show how you would prepare five solutions of aqueous
hydrogen peroxide. Make sure that the correct units are recorded.
expt No. volume of H2 O2 volume of H2O concentration of H2O2
1
2
3
4
5

Note That: I just dont understand where to get all the amounts to fill in to the table!

you need to assume your own values but remember to keep the total volume constant... for dilution use the formula c1v1=c2v2

Can you give me several examples pleasee!!! the exam is tomorow!

 

[beacon_of_light]

guys oct nov 09 51 q2 how do we find moles?????

wts da ratio!!

In the table of results, you've already calculated the mass of zinc and iodine used...
Now divide these masses by their respective atomic masses to obtain moles...
Then find the ratio of iodine to zinc ...

y is da ratio IODINE TO ZINC AND NOT ZINC TO IODINE????

it could be both ... I2 to zinc would be 2:1 and zinc to iodine would be 1:2 ...

 

[beacon_of_light]

they say STRAIGHT LINES!!

HOW R WE SUPPOSE TO KNOW THT A CURIVE IS INVOLVED!!!!

look the question gives you a clue that the solubility varies above and below a certain temperature(transition temperature) and you can easily see that a straight line can not be drawn from the first set of points ... so draw a curve...while the second set of points are very very close so draw a straight line... you need to read the question carefully and at the same time judge it very well ...

 

[boy2011]

PLSSSSS showww sum example reagrding hw to make dilutions???C1V1=C2V2 but wat value we have to take in C2? and V1 nd V2???plssss reply asap

 

[comptech8]

I use the formula: V1C2=V2C1

Where V1=50cm3, V2=10cm3, C1=2mol/dm3

Use this formula and u can get C2 as 0.4mol/dm3

 

[awesome94]

viewtopic.php?f=26&t=6805
try this... someone posted some really awsm notes