Chemistry: Post your doubts here!

[princess Anu]

In this case, the cis-trans is the same as the trans-cis. So your 2nd and 4th are essentially the same molecules.

The often neglected part is the the molecule can rotate (twist) along the C-C single bond.

View attachment 51212

even if those single bonded carbon atoms are double bonded with other carbon atoms?

 

[Metanoia]

even if those single bonded carbon atoms are double bonded with other carbon atoms?

Yes. The rotation is between the C-C bonds, doesn't matter C atoms are attached else where.
I can't find a video on C=C-C=C, but here is a video of C-C-C-C, where the rotation along the middle bond is shown.

 

[cashew]

http://papers.xtremepapers.com/CIE/...d AS Level/Chemistry (9701)/9701_s09_qp_1.pdf
mcq 5 and 6. I am stuck, can someone explain me the answers?

 

[Metanoia]

http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Chemistry (9701)/9701_s09_qp_1.pdf
mcq 5 and 6. I am stuck, can someone explain me the answers?

Hi there, could you share your thoughts on the 2 questions so I know why you are stuck.

 

[cashew]

Hi there, could you share your thoughts on the 2 questions so I know why you are stuck.

hey metonia, I am done with q6 but i was still wondering for question 5, why can't option B and D be the answers?
thanks in advance

 

[cashew]

why C? ._.

 

[Metanoia]

hey metonia, I am done with q6 but i was still wondering for question 5, why can't option B and D be the answers?
thanks in advance

What are your carbon products for B and D? And their bond angles?

View attachment 51215

why C? ._.

What wrong answer did you choose?

 

[cashew]

What are your carbon products for B and D? And their bond angles?


What wrong answer did you choose?

B and then i cut it and chose D :/

 

[Metanoia]

View attachment 51215

why C? ._.

B and then i cut it and chose D :/

Covalent forces is the bond of an I atom to another I atom.
It is very strong and isn't broken during such heating, i.e. the I2 molecule is not broken into two iodine atoms.

Induced dipole-dipole is the weak attraction of an I2 molecule to another I2 molecule. Heating overcomes these forces and separate an I2 molecule from another molecule.

I couldn't find illustrations of iodine molecules, so will use CO2 as example.

 

[cashew]

Covalent forces is the bond of an I atom to another I atom.
It is very strong and isn't broken during such heating, i.e. the I2 molecule is not broken into two iodine atoms.

Induced dipole-dipole is the weak attraction of an I2 molecule to another I2 molecule. Heating overcomes these forces and separate an I2 molecule from another molecule.

I couldn't find illustrations of iodine molecules, so will use CO2 as example.

Woah, thanks a lot bro

 

[ashcull14]

In the gas phase, aluminium and a transition element require the same amount of energy to form one mole of an ion with a 2+ charge.
What is the transition element?

 

[cashew]

11 In some fireworks there is a reaction between powdered aluminium and powdered barium nitrate in which heat is evolved and an unreactive gas is produced. What is the equation for this reaction?
A 2Al + Ba(NO3)2 → Al2O3 + BaO + 2NO
B 4Al + 4Ba(NO3)2 → 2Al2O3 + 4Ba(NO2)2 + O2
C 10Al + 3Ba(NO3)2 → 5Al2O3 + 3BaO + 3N2
D 10Al + 18Ba(NO3)2 → 10Al(NO3)3 + 18BaO + 3N2
why doesn aluminium form Al2O3 instead of Al(NO3)3?

 

[Metanoia]

In the gas phase, aluminium and a transition element require the same amount of energy to form one mole of an ion with a 2+ charge.
What is the transition element?

I suppose this is an MCQ question? Use the data booklet and find the sum of 1st I.E and 2nd I.E of Al (577+1820 = 2397) , then see which of the transition metals give the same result.

11 In some fireworks there is a reaction between powdered aluminium and powdered barium nitrate in which heat is evolved and an unreactive gas is produced. What is the equation for this reaction?
A 2Al + Ba(NO3)2 → Al2O3 + BaO + 2NO
B 4Al + 4Ba(NO3)2 → 2Al2O3 + 4Ba(NO2)2 + O2
C 10Al + 3Ba(NO3)2 → 5Al2O3 + 3BaO + 3N2
D 10Al + 18Ba(NO3)2 → 10Al(NO3)3 + 18BaO + 3N2
why doesn aluminium form Al2O3 instead of Al(NO3)3?

Recall that most metal nitrates decompose under heat to produce metal oxides, so even IF Al(NO3)3 is formed during the reaction, it would decompose to form Al2O3.

 

[cashew]

I suppose this is an MCQ question? Use the data booklet and find the sum of 1st I.E and 2nd I.E of Al (577+1820 = 2397) , then see which of the transition metals give the same result.

View attachment 51229
View attachment 51230



Recall that most metal nitrates decompose under heat to produce metal oxides, so even IF Al(NO3)3 is formed during the reaction, it would decompose to form Al2O3.

Thanks again
May God bless you.

 

[Metanoia]

Thanks again
May God bless you.

No problem, you're welcome.

 

[ashcull14]

I suppose this is an MCQ question? Use the data booklet and find the sum of 1st I.E and 2nd I.E of Al (577+1820 = 2397) , then see which of the transition metals give the same result.

View attachment 51229
View attachment 51230



Recall that most metal nitrates decompose under heat to produce metal oxides, so even IF Al(NO3)3 is formed during the reaction, it would decompose to form Al2O3.

THNKS CN U ANS DIS PLEASE?
Q-In the gas phase, aluminium and a transition element require the same amount of energy to form one mole of an ion with a 2+ charge.
What is the transition element?

 

[ashcull14]

 

[cashew]

View attachment 51231

1 and 3?

 

[Metanoia]

THNKS CN U ANS DIS PLEASE?
Q-In the gas phase, aluminium and a transition element require the same amount of energy to form one mole of an ion with a 2+ charge.
What is the transition element?

Hmm..I already answered it in the post, it's cobalt.

 

[Metanoia]

How to do these ??

The 17 cm3 of NaOH used, is that a figure obtained by actually carrying out the experiment or just a number randomly chosen?

If randomly chosen, it might mean that the final answer of the formula of RCO2H would not make sense.