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Help!: Organic Chem Question

Please Help!

Myrcene, C10H16, is a naturally occurring oil present in bay leaves. The structure of myrcene is shown below:

See attachment

a) Reaction of a 0.100 mol sample of myrcene with hydrogen at room temperature and pressure (r.t.p.) produced a saturated alkane, A.

ii) Determine the molecular formula of the saturated alkane, A.

b)

Squalene is a naturally occuring oil present in shark-liver oil. A 0.100 mol sample of the squalene reacted with 14.4 dm3 of hydrogen at r.t.p to form a saturated hydrocarbon C30H62.

i) Calculate how many double bonds there are in each molecule of squalene.
Reply 1
to find the structure of A for each double bond a hydrogen atom is added to each side and the double bond dissappears giving a molecular formula of C10H22 (i think, if i can count)

for the 2nd part you need to work out number of moles of hydrogen used then devide it by 0.1 then by 2 to find the number of double bonds, as for each 0.1 mole of squalene 0.05 moles of hydrogen is used to satuarte each double bond

Hope that helps, it sounds clear as mud when i read it back, thats the first chem i did since i left the exam!
supreme
Please Help!

Myrcene, C10H16, is a naturally occurring oil present in bay leaves. The structure of myrcene is shown below:

See attachment

a) Reaction of a 0.100 mol sample of myrcene with hydrogen at room temperature and pressure (r.t.p.) produced a saturated alkane, A.

ii) Determine the molecular formula of the saturated alkane, A.


You should be able to do this, there is only one double bond in the molecule.


b)

Squalene is a naturally occuring oil present in shark-liver oil. A 0.100 mol sample of the squalene reacted with 14.4 dm3 of hydrogen at r.t.p to form a saturated hydrocarbon C30H62.

i) Calculate how many double bonds there are in each molecule of squalene.


You need to work out the number of moles of hydrogen using PV=nRT where P is pressure, V is volume (14.4 dm3 in this case), n is number of moles, R is the gas constant 8.314 JK-1mol-1, T is temperature in K. If you have the number of moles of hydrogen, divide by the number of moles of squalene and that is the number of double bonds, easy!
Reply 3
cobra01977
to find the structure of A for each double bond a hydrogen atom is added to each side and the double bond dissappears giving a molecular formula of C10H22 (i think, if i can count)

for the 2nd part you need to work out number of moles of hydrogen used then devide it by 0.1 then by 2 to find the number of double bonds, as for each 0.1 mole of squalene 0.05 moles of hydrogen is used to satuarte each double bond

Hope that helps, it sounds clear as mud when i read it back, thats the first chem i did since i left the exam!


ChemistBoy
You should be able to do this, there is only one double bond in the molecule.

You need to work out the number of moles of hydrogen using PV=nRT where P is pressure, V is volume (14.4 dm3 in this case), n is number of moles, R is the gas constant 8.314 JK-1mol-1, T is temperature in K. If you have the number of moles of hydrogen, divide by the number of moles of squalene and that is the number of double bonds, easy!


Thanks cobra01977 & ChemistBoy :biggrin: :biggrin: :biggrin: :biggrin: :biggrin: :biggrin: