Chemistry: Post your doubts here!

[smartangel]

For 23, thr will be 9 products formed, including Br2, ethane, n HBr...
the other 6 will be like CH3CH2Br, CH3CHBr2, CH3CBr3....n so on..
Hope i helped!!


r u sure the ms said C?? which ppr, nywy??

http://www.xtremepapers.com/papers/...d AS Level/Chemistry (9701)/9701_w05_qp_1.pdf Q20..im sorry the answer is B. my question is that whats the other isomer besides cis trans?

 

[Inert.Phantom]

can u try for the enthalp change question too

 

[Inert.Phantom]

Given the following enthalpy changes,
I2(g) + 3Cl2(g) → 2ICl3(s) ∆H = –214kJmol
I2(s) → I2(g) ∆H = +38kJmol

What is the standard enthalpy change of formation of iodine trichloride, ICl3(s)?
A +176kJmol
B –88kJmol
C –176kJmol
D –214kJmol

 

[smartangel]

http://www.xtremepapers.com/papers/...d AS Level/Chemistry (9701)/9701_w03_qp_1.pdf
Q27..why is the answer sulfuric acid..can someone plz tell me the rxn these compounds undergo with H2SO4?

 

[smartangel]

Given the following enthalpy changes,
I2(g) + 3Cl2(g) → 2ICl3(s) ∆H = –214kJmol
I2(s) → I2(g) ∆H = +38kJmol

What is the standard enthalpy change of formation of iodine trichloride, ICl3(s)?
A +176kJmol
B –88kJmol
C –176kJmol
D –214kJmol

whats the answer?

 

[Inert.Phantom]

Given the following enthalpy changes,
I2(g) + 3Cl2(g) → 2ICl3(s) ∆H = –214kJmol
I2(s) → I2(g) ∆H = +38kJmol

What is the standard enthalpy change of formation of iodine trichloride, ICl3(s)?
A +176kJmol
B –88kJmol
C –176kJmol
D –214kJmol​

whats the answer?...........................

its B

 

[smartangel]

Given the following enthalpy changes,​

I2(g) + 3Cl2(g) → 2ICl3(s) ∆H = –214kJmol​

I2(s) → I2(g) ∆H = +38kJmol​

​

What is the standard enthalpy change of formation of iodine trichloride, ICl3(s)?​

A +176kJmol​

B –88kJmol​

C –176kJmol​

D –214kJmol​

whats the answer?...........................

its B

its going to be 2x - 38 = -214. solve for x.

 

[Inert.Phantom]

i dont get it ...
solve it please

 

[smartangel]

Please explain how is the answer A??

 

[smartangel]

in ester formation, OH is from the acid and H from the alcohol combine to form water or is it the opposite?

 

[saudha]

Chlorofluoroalkanes, commonly known as CFCs, undergo homolytic fission by ultraviolet
irradiation in the stratosphere.
Which radical could result from this irradiation of CHFClCF2Cl?
A) CHFClC·FCl
B) C·HClCF2Cl
C) C·HFCF2Cl
D) C·FClCF2Cl
how do u get this ?

 

[smzimran]

Chlorofluoroalkanes, commonly known as CFCs, undergo homolytic fission by ultraviolet
irradiation in the stratosphere.
Which radical could result from this irradiation of CHFClCF2Cl?
A) CHFClC·FCl
B) C·HClCF2Cl
C) C·HFCF2Cl
D) C·FClCF2Cl
how do u get this ?

AoA,
Go a little back, in this thread i have answered the question before!

 

[smzimran]

in ester formation, OH is from the acid and H from the alcohol combine to form water or is it the opposite?

AoA,
Its the opposite
R---COO---H
R---CH2---OH
The red coloured bonds break in each case
So, H from acid and OH from alcohol form water

 

[saudha]

What is the number of molecules in 500 cm3
of oxygen under room conditions?
A 1.25 x 10^22
B 1.34 x 10^22
C 3.0 x 10^22
D 3.0 x 10^26

how do u get A?

 

[smzimran]

Please explain how is the answer A??

This question needs you to use the values of 1st and 2nd ionisation energies
Check which elements sum of 1st two I.Es equals that of Al

 

[smzimran]

What is the number of molecules in 500 cm3
of oxygen under room conditions?
A 1.25 x 10^22
B 1.34 x 10^22
C 3.0 x 10^22
D 3.0 x 10^26

how do u get A?

500 cm3 of O2 means (500/1000) dm3 = 0.5 dm3

In 24 dm3 (one mole), there are (6.02 * 10^23) molecules
In 1 dm3, there are {(6.02 * 10^23) / 24} molecules

So in 0.5 dm3, there will be
= 0.5 * {(6.02 * 10^23) / 24}
= 1.25 * 10^22 molecules

So, the correct answer is A

 

[saudha]

Which of the following solids has a simple molecular lattice?
A magnesium oxide
B sodium
C silicon(IV) oxide
D sulphur

why D? why not B?

 

[saudha]

How many structural and cis-trans isomers are there for dichloropropene, C3H4Cl2?
A 3 B 5 C 6 D 7
is there any other way other than drawing all of them?

 

[smzimran]

Given the following enthalpy changes,​

I2(g) + 3Cl2(g) → 2ICl3(s) ∆H = –214kJmol​

I2(s) → I2(g) ∆H = +38kJmol​

What is the standard enthalpy change of formation of iodine trichloride, ICl3(s)?​

A +176kJmol​

B –88kJmol​

C –176kJmol​

D –214kJmol​

whats the answer?...........................

its B

See the image

 

[smzimran]

Which of the following solids has a simple molecular lattice?
A magnesium oxide
B sodium
C silicon(IV) oxide
D sulphur

why D? why not B?

Sodium has metallic bonding,
positive ions bonded by sea of electrons, thats why not B