Qualification > Sciences
Edexcel CHEMISTRY DOUBTS!!!!
AS01:
its the same here too i finished doing all of the past papers and i don't have any left can you plz email me some of the questions on chemistry too.
by the way how come you know everything have you completed your A levels?
AS01:
hey can you plz say be what is the equation of bond enthalpy and mean bond enthalpy?
i know there definition. but the way they ask in exam i am unable to recognise whether which is bond enthalpy and which one is not.
for example for the reaction given below
1/4CH4(g)=>1/4C(g)+H(g)
why is this the mean bond enthalpy of CH4 bond not CH4(g)=>C(g)+2H2(g)?
plz explain this in detail.
AS01:
The human body contains around 0.025 g of iodine molecules, I2. Which of the
following shows the number of iodine atoms in 0.025 g of I2?
The Avogadro constant is 6.02 × 1023 mol–1.
Why the answer is this:-
0.025/126.9*6.02*10^23
not 0.025/253.8*6.02*10^23?
Blizz_rb93:
--- Quote from: AS01 on January 12, 2012, 07:23:08 pm ---The human body contains around 0.025 g of iodine molecules, I2. Which of the
following shows the number of iodine atoms in 0.025 g of I2?
The Avogadro constant is 6.02 × 1023 mol–1.
Why the answer is this:-
0.025/126.9*6.02*10^23
not 0.025/253.8*6.02*10^23?
--- End quote ---
i was wondering the same thing :/
& i have smth also
this is from Jan 2011 unit 1
question 3:
The Avogadro constant is 6.0 x 10^23 mol-1. Therefore the numbers of atoms in 1 mol of carbon dioxide is :
why is the answer 1.8 x 10^24 and not 6.0 x 10^23 :/
Malak:
--- Quote from: AS01 on January 12, 2012, 07:23:08 pm ---The human body contains around 0.025 g of iodine molecules, I2. Which of the
following shows the number of iodine atoms in 0.025 g of I2?
The Avogadro constant is 6.02 × 1023 mol–1.
Why the answer is this:-
0.025/126.9*6.02*10^23
not 0.025/253.8*6.02*10^23?
--- End quote ---
I suppose because the question asks for atoms of iodine and not molecules?
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