[snowie1010]

can some1 plz help me with these. i have an assignment due and im not sure how to do these 2 Q's

1) If 176 grams of sugar are dissolved in 5.00 L of petrol, how much sugar remains in the petrol (3 sig. fig.) following a single extraction with 3.00 L of water if the partition coefficient is 2.00.

i used k=S2/S1  i got a value of 52.8g of sugar?? need to know if this is right or where i might have gone wrong

2)Methyl hydroperoxide is dissolved in 388 mL of water. How many 66 mL extractions with ether are required to remove more than 82% of the peroxide from the water is the partition coefficient is 2. (Methyl hydroperoxide is more soluble in dimethyl ether than water)

using qⁿ=(v1/v1+kv2)ⁿ i got a value of n=0.67 which i really don't think should be right?? not sure where i would have gone wrong.

this is my first post, any help would be great, thanks

[JGK]

Please post your calculations in full, it will be easier for us to spot where you went awry

[snowie1010]

im trying to teach my self here, but for the 1st 1 i just did

176/5=35.2g/L
then
2= 35.2/(x/3)
x=52.8g

for the 2nd i didn't really have much clue

0.82 = ln 0.746 * n

n = 0.67

[JGK]

For the first one you need to use q=(v1/v1+kv2). then apply q (fraction of the total patritioned) to the 176g

For the second one you need to use qn=(v1/v1+kv2)n and increase n on the right side until qn is > 0.82