Ammonia question help

http://www.ocr.org.uk/Images/171755-unit-h033-01-foundations-of-chemistry-sample-assessment-materials.pdf

For Q2 the answer is C ( C The bonds between the ammonia molecules are weak). Can someone explain as this is very vague answer. What bond is thing referring to ?

Also for 10b) why is the answer c?

Thanks

Reply 1

username986184

Original post by coconut64

Intermolecular

Original post by coconut64

Also for 10b) why is the answer c?

Write out the equation. Look at the stoichiometry. One of the reactants is in excess.

Reply 2

coconut64

Original post by TeachChemistry

Intermolecular

Write out the equation. Look at the stoichiometry. One of the reactants is in excess.

For q2 why is the intermolecular forces bewteen the molecules considered rather than the bonds within the molecule for the boiling point?

For 10b) the ratio is 1:3 : 2 I am still unsure as I have used this info and did 500/2 to give me 250 cm^3 as there are two moles of ammonia. Thanks

help???

Original post by coconut64

help???

Let's deal with Q2.

When water boils, for example, which bonds break during the liquid to gas transition?

Reply 5

coconut64

Original post by TeachChemistry

Let's deal with Q2.

When water boils, for example, which bonds break during the liquid to gas transition?

Hydrogen bonds?

Reply 6

username986184

Original post by coconut64

Hydrogen bonds?

Exactly - the intermolecular bonds. The bonds between molecules. And so it is with ammonia.

So the answer is C. It can't be A because that is not true. B is true but so what - it has no relevance to the question. D is true but these bonds have nothing to do with state.

A
The bonds between the nitrogen and hydrogen atoms in ammonia are weak.

B
Nitrogen and hydrogen have very low boiling points.

C
The bonds between the ammonia molecules are weak.

D
Ammonia is covalently bonded

Reply 7

coconut64

Original post by TeachChemistry

Why do they call the IMF between the ammonia molecules 'bonds' , aren't they intermolecular forces though? Thanks Also can you explain 10b?

Reply 8

username986184

Original post by coconut64

Why do they call the IMF between the ammonia molecules 'bonds' , aren't they intermolecular forces though? Thanks Also can you explain 10b?

the terms bonds and forces are synonymous in this situation. I am surprised you have not heard this before.

Reply 9

username986184

Original post by coconut64

Also can you explain 10b?

Look at the Haber process balanced equation and answer the following. What is the MAXIMUM volume of N₂ that can react with 300 cm³ of H₂?

Reply 10

coconut64

Original post by TeachChemistry

the terms bonds and forces are synonymous in this situation. I am surprised you have not heard this before.

I was taught that they are simply called intermolecular forces. Bonds are within the molecule that what I learnt. Please could you explain 10b? thanks

Reply 11

username986184

Original post by coconut64

I was taught that they are simply called intermolecular forces. Bonds are within the molecule that what I learnt.

But you just used the term hydrogen bonds. Why did you not call these 'hydrogen intermolecular forces'?

(edited 7 years ago)

Reply 12

coconut64

Original post by TeachChemistry

Look at the Haber process balanced equation and answer the following. What is the MAXIMUM volume of N₂ that can react with 300 cm³ of H₂?

So only 100 cm³ of N2 will react. And if there are 2 moles of ammonia, surely it will be 100+300 then half of the total , giving 200?

Reply 13

username986184

Original post by coconut64

So only 100 cm³ of N2 will react. And if there are 2 moles of ammonia, surely it will be 100+300 then half of the total , giving 200?

And what about the unreacted nitrogen?

Reply 14

coconut64

Original post by TeachChemistry

And what about the unreacted nitrogen?

Thanks for the help, I really appreciate it. I have got other questions as well if you don't mind helping. Many thanks.

Reply 15

username986184

Original post by coconut64

Thanks for the help, I really appreciate it. I have got other questions as well if you don't mind helping. Many thanks.

Does that mean you understand 10b now?

Reply 16

coconut64

Original post by TeachChemistry

Does that mean you understand 10b now?

Yes, because the question is not asking you the volume of the final product but instead the volume of everything left over after the reaction. Since there is some unreacted ammonia, the total adds up to 300