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http://papers.xtremepapers.com/CIE/...d AS Level/Chemistry (9701)/9701_s03_qp_4.pdf
please explain Q2 part b
please explain Q2 part b
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The ions present in a solution of ethanol and H2SO4 are:which ions are present in a solution of ethanol in an excess of concentrated sulphuric acid?
1) CH3CH2O^-1
2) CH3CH2^+OH2
3) HSO4^-1
First:View attachment 34691
Can anyone explain this question?
i)can anyone tell me the answer and explain why
Please
The answer is A.can anyone tell me the answer and explain why
Please
How doesn't D make sense we can just find the formation of CH4 and divide by 4?The answer is A.
When using atomization energies, we can write the equation as:
C + 2 (H-H) => 4 (C-H)
Atomization energy of C will be given
Atomization of H2 will be given which can be used to calculate H-H:
1/2 H-H = Atomization energy
According to equation:
Formation of methane = bond energy = product energy - reactant energy
B is not the answer because we can only calculate the enthalpy of reaction using those values.
C is not the answer because there is no formula connecting formation and combustion for this question.
D is not the answer because it doesn't make sense.
The definition of enthalpy energy of formation is defined as the energy change that takes place when 1 mole of a substance is formed from elements in it's standard state under standard conditions. It has nothing to do with bond energy. To make it clearer, if you take a look at the data booklet, the bond energy of CH bond is 413 kJ/mol while the enthalpy change of formation of CH4 is -75 kJ/mol.How doesn't D make sense we can just find the formation of CH4 and divide by 4?
Thanks
thanks so much could you help me with 2 other questions pleaseThe definition of enthalpy energy of formation is defined as the energy change that takes place when 1 mole of a substance is formed from elements in it's standard state under standard conditions. It has nothing to do with bond energy. To make it clearer, if you take a look at the data booklet, the bond energy of CH bond is 413 kJ/mol while the enthalpy change of formation of CH4 is -75 kJ/mol.
in the Ms they take Mass as the volume of acid used why is that?
Can anyone help me out with this one?
Why can't the answer be B??
The answer cannot be B because if we use the combustion values we need 1 mole of PbO, in which case it will no longer have 1 mole of Pb3O4 and we will not be able to equate the formation and combustion values. The answer is D because when both values of formation are given we can simply use the formula and get our answer.Can anyone help me out with this one?
Why can't the answer be B??
Have they used 20 cm^3?in the Ms they take Mass as the volume of acid used why is that?
they have used 30 cm^3 as the MASS but 30 cm^3 is the volume of the acid used? do we always just take volume instead of mass?Have they used 20 cm^3?
That is actually not so surprising because for liquids or aqueous substances, the formula for energy gained is in fact q=Vc(T2-T1).they have used 30 cm^3 as the MASS but 30 cm^3 is the volume of the acid used? do we always just take volume instead of mass?
it was for me i did'nt know that as i just started my ASThat is actually not so surprising because for liquids or aqueous substances, the formula for energy gained is in fact q=Vc(T2-T1).
remember mr manoj's notes??? he said 1gm= 1cm^3 ... so 30cm^3 would be 30gms.they have used 30 cm^3 as the MASS but 30 cm^3 is the volume of the acid used? do we always just take volume instead of mass?
Would you like to mention the full question please, there must be more added to this question. You just can't tell it simply that it is this element or this. Well All the nitrates in Group 2 undergo thermal decomposition to give the metal oxide, nitrogen dioxide and oxygen. So i just can't simply say that it is Mg, Ca ...etc. Also as you go down the group, these metal nitrates become more stable to heat. So you need to heat Ca more than Mg. Because Ca is below Mg, thus it is more heat stable than Mg.AoA, please answer this for me.. A 5g sample of an anhydrous group 2 metal nitrate loss 3.29g mass on strong heating. What metal is present. How do u solve it?
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