Qualification > Sciences
Edexcel CHEMISTRY DOUBTS!!!!
obstacle26:
Unit 1 sample assessment Paper, MCQ 3.Buckminsterfullerene is a carbon molecule with formula C60 which can trap metal ions in its structure. Which of the following compounds of buckminsterfullerene would give a line of mass/charge ratio at 837.3 in a mass spectrometer?
A Na4C60
B K3C60
C Ca3C60
D AgC60
Answer is B , can some body explain the logic?
Meticulous:
m/z ratio= m/1
so calc the Mr of all compounds. It's B.
raimunts:
--- Quote from: vanibharutham on May 17, 2010, 08:49:04 pm ---One element must be O2 for it to be an enthalpy of combustion
in the attached file
1 = standard enthalpy of combustion of A
2 = standard enthalpy of formation of A
3 = standard enthalpy of formation of B
4 = standard enthalpy of formation of C
NB. O2 does an enthalpy of formation of 0 kJ/mol
using Hess's Law
1 = 3 + 4 - 2
just substitute in the values
--- End quote ---
Thanks a lot. Crystal clear. So it's only for enthalpy change of combustion...nothing for formation?
raimunts:
For Edexcel AS Chemistry [New Spec] is knowledge of Unit 2 required in Unit 1? I'm asking because I've not been able to finish Unit 2 yet, and I'm wondering if it will negatively affect my Unit 1 exam. Precisely, which parts of Unit 2 are we supposed to learn when sitting for Unit 1?
Darth Austrakast:
Well the Mechanism chapter in Unit 2 might help you with Unit 1 Organic Chemistry...........but you technically don't have to learn anything...you can just go through the topics--specially shapes of molecules,inter-molecular forces etc which are related to structure and bonding
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