Chemistry MCQ thread...

[A*****]

View attachment 64385
ANSWER IS D.
Please explain how carbon is removed.
And why B is not an answer.

Which year is it from?

 

[Hamnah Zahoor]

View attachment 64385
ANSWER IS D.
Please explain how carbon is removed.
And why B is not an answer.

Well you checked the marking scheme wrong
the question is from may june 2005 and according to the marking scheme the answer is B not D.

 

[EvamSS]

View attachment 62472 How do you even break this question down

answer is 7

 

[Hahaiwanttodie]

Is the answer o.425

if it is then first find the moles of nitrogen gas then take 15% of the moles
then take mole ratio with ammonia produced that would be 1:2
then you can use the formula n=m/Mr to find the mass of ammonia produced

That is incorrect. The actual answer is 2.83.

 

[shah kai]

 

[UMRASDE]

12 Which chlorine compound has bonding that can be described as ionic with some covalent
character?
A NaCl B MgCl2 C AlCl3 D SiCl4
WHY ITS B ?????

Aluminum chLorien is an ionic bond with high degree of covalent character
Magnesium chloride is a covalent bond with some covalent character,hence magnesium chloride is the answer.more information can be found in this link https://www.ibchem.com/IB16/02.62.htm

 

[blabla25]

View attachment 64385
ANSWER IS D.
Please explain how carbon is removed.
And why B is not an answer.

where is this question from, could u recheck the ms?

 

[Bluey-_-]

Is the answer o.425

if it is then first find the moles of nitrogen gas then take 15% of the moles
then take mole ratio with ammonia produced that would be 1:2
then you can use the formula n=m/Mr to find the mass of ammonia produced

Can u explain this part a bit more
Liek with more detial am a bit lost

 

[xultvre]

Which statement about the standard enthalpy change of formation of carbon dioxide is correct?

A It is equal to the standard enthalpy change of combustion of carbon.

B It is equal to twice the bond energy of the C=O bond.

C It is the energy released when one mole of carbon dioxide is formed from carbon at the
temperature of combustion of the carbon.

D It is the same for carbon dioxide produced from graphite and from diamond.

its A but why it is not C ?!