chem question

[nid404]

why would you multiply it by 3

[Q80BOY]

1-1.33
multiply by 3
3-4
formula is Pb₃O₄

i LOVE u !!!

thats what i wanted .. what do i multiply it by .. ur the man dude ..

thnxx alot !!

[Q80BOY]

why would you multiply it by 3

to turn the decimal into a whole number ..

[slvri]

why would you multiply it by 3

to make the ratio of lead to oxygen a whole number
since 1.33 is basically 4/3
so1*3:4/3*3=3:4
and q80boy.........no problem

[Ghost Of Highbury]

hey guys, i have another question ..

Find the Empeical Formula of the following oxide of lead.

It contains 9.7g of lead to every 1g of oxygen

(RAM values .. Pb= 207, O= 16)

the answer is Pb₃O₄

i dunno what to do after we divide by the smallest answer =/

please help

u had ritten Pb3O3...wen asked if there was any change ..u said "no" the q was correct..

and y do v multiply only with 3 .........  u need to divide the mass of d substance wid 228.28 and then multiply it with PbO1.33

[slvri]

to make the ratio a whole number......
1.33 isnt close enough to 1 to make it approximately equal to 1.........but if it were 1.03 i would have approximated it to 1

[Ghost Of Highbury]

to make the ratio a whole number......
1.33 isnt close enough to 1 to make it approximately equal to 1.........but if it were 1.03 i would have approximated it to 1

ohh..okk..

[Bani]

Hey guys!
Here is a question I need help on:
i)-Oceanographers studying plankton found that a sample of seawater contained 1.20 nanomol dm^-3 of chlorophyll, C55H77MgN4O5. (1 nanomol= 1*10^-9 mol)
What mass of magnesium would be present in 1.00 cm^3 of this sample of seawater? Give your answer to three significant figures.

ii)- X-ray diffraction can be used to locate atoms or ions in molecules like chlorophyll. X-rays are scattered by the electrons in atoms and ions. In chlorophyll the atoms of one of the elements still cannot be located with certainty by this technique.
Suggest which element is most difficult to locate? (i think its hydrogen....not sure)

thanks in advance!

[nid404]

ok here's the answer

no on moles= 1.2X10^-9 in one dm^3
therefore mass of Mg= 1.2X10^-9 X 24(mass of one mole)/ 1000( 1dm^3=1000cm^3)
=2.88X10^-11 g

check if it's right plz

and for the second one

I too think it's hydrogen because it has the least no of electrons in it's atom...which makes it difficult to locate it....diffraction is not enough to locate it

[mousa]

ok here's the answer

no on moles= 1.2X10^-9 in one dm^3
therefore mass of Mg= 1.2X10^-9 X 24(mass of one mole)/ 1000( 1dm^3=1000cm^3)
=2.88X10^-11 g

check if it's right plz

and for the second one

I too think it's hydrogen because it has the least no of electrons in it's atom...which makes it difficult to locate it....diffraction is not enough to locate it

yup.. thats right,i got the same answerss

[Bani]

yup.. thats right,i got the same answerss

Yippeeee!
yup they are right!
thanks guys!

[Q80BOY]

heyy guyz !!

my chem teacher is letting us live in hell! Moles and moles and more moles!

i need ur help in a couple of questions:

1. 0.0185 mol of hydrated MgSO₄.xH₂O has a mass of 4.56g. Calculate the number of molecules of water of crystallisation in the salt.

ur help is highly appreciated!!

[nid404]

ok here u go

Mass og 1 mol of MgSO₄=120g
mass of 0.0185mol=120X0.0185=2.22g
Mass of water=4.56-2.22=2.34g
1 mole of water=18g
there x moles= 2.34
no of moles of water in 0.0185 moles of hydrated magnesium sulphate=0.13
therefore no of moles of water=0.13/0.0185=7 moles
therefore MgSO₄.7H₂O

Cross check
Mass of 1 mole of MgSO₄.7H₂O=246g
4.56g= how many moles
cross multiply
gives 0.0185 moles

[Q80BOY]

thnxxxx

[Q80BOY]

heloooo .. its me again

i got a part of a question i need help with ..

in the following reaction ..

2NaOH + H₂SO₄ --> Na₂SO₄ + 2H₂O

what would be observed if peices of red and blue litmus paper were added to Sodium sulfate after the reaction?

ur help is highly appreciated guyzz!!