GemGoth
Badges: 9
Rep:
?
#1
Report Thread starter 1 year ago
#1
I really don't understand my chemistry hw about Le Chatelier's principle and its link to Dynamic Equilibrium.

The first equation is=CH4+H2O------>CO+3H2
-If the temperature of equilibrium is increased what would happen to the yield of hydrogen?Explain your reasoning.
-If the pressure of equilibrium was increased,what would happen to the yield of hydrogen?Explain your reasoning.

The second equation is=CO+H2O------>CO2+H2
-If the temperature of equilibrium is increased what would happen to the yield of hydrogen?Explain your reasoning.
-If the pressure of equilibrium was increased,what would happen to the yield of hydrogen?Explain your reasoning.

Any help is appreciated
0
reply
BobbJo
Badges: 12
Rep:
?
#2
Report 1 year ago
#2
1st.
If temperature increases, equilbrium shifts to the right as forward reaction is endothermic. Yield of hydrogen increases
If pressure increases, equilbrium shifts to the left as fewer moles of gas on the left. Yield of hydrogen decreases

2nd.
If temperature increases, equilibrium shifts to the right as forward reaction is endothermic. Yield of hydrogen increases
In pressure increases, no change in equilbrium as same number of moles of gas. Yield of hydrogen is unchanged
0
reply
GemGoth
Badges: 9
Rep:
?
#3
Report Thread starter 1 year ago
#3
(Original post by BobbJo)
1st.
If temperature increases, equilibrium shifts to the right as forward reaction is endothermic. Yield of hydrogen increases
If pressure increases, equilibrium shifts to the left as fewer moles of gas on the left. Yield of hydrogen decreases

2nd.
If temperature increases, equilibrium shifts to the right as forward reaction is endothermic. Yield of hydrogen increases
In pressure increases, no change in equilibrium as same number of moles of gas. Yield of hydrogen is unchanged
Thank you so much,I just had one more question,so for example for the 1st one,does equilibrium shifts to the right as when the temperature increased,the reaction was exothermic so it favoured the right one,making it endothermic???
0
reply
BobbJo
Badges: 12
Rep:
?
#4
Report 1 year ago
#4
(Original post by GemGoth)
Thank you so much,I just had one more question,so for example for the 1st one,does equilibrium shifts to the right as when the temperature increased,the reaction was exothermic so it favoured the right one,making it endothermic???
No you should be given the enthalpy change. The enthalpy change is positive. Hence the forward reaction is endothermic. From this, you deduce that an increase in temperature favours the forward reaction.

You can't use the backward logic because you can't know which reaction is favoured when you don't know which reaction is endo/exo

If you are not given values of enthalpy changes, work them out using bond energies from the data booklet.
0
reply
GemGoth
Badges: 9
Rep:
?
#5
Report Thread starter 1 year ago
#5
(Original post by BobbJo)
No you should be given the enthalpy change. The enthalpy change is positive. Hence the forward reaction is endothermic. From this, you deduce that an increase in temperature favours the forward reaction.

You can't use the backward logic because you can't know which reaction is favoured when you don't know which reaction is endo/exo

If you are not given values of enthalpy changes, work them out using bond energies from the data booklet.
Oh okay,thank you
0
reply
GemGoth
Badges: 9
Rep:
?
#6
Report Thread starter 1 year ago
#6
(Original post by BobbJo)
1st.
If temperature increases, equilbrium shifts to the right as forward reaction is endothermic. Yield of hydrogen increases
If pressure increases, equilbrium shifts to the left as fewer moles of gas on the left. Yield of hydrogen decreases

2nd.
If temperature increases, equilibrium shifts to the right as forward reaction is endothermic. Yield of hydrogen increases
In pressure increases, no change in equilbrium as same number of moles of gas. Yield of hydrogen is unchanged
For number 2 and the first bullet point if the energy change of the forward reaction is -42kJ/mol,would the yield of hydrogen still increase?
0
reply
BobbJo
Badges: 12
Rep:
?
#7
Report 1 year ago
#7
(Original post by GemGoth)
For number 2 and the first bullet point if the energy change of the forward reaction is -42kJ/mol,would the yield of hydrogen still increase?
No it would decrease. According to Le Chatelier, the equilibrium will shift so as to decrease the temperature. Hence backward reaction is favoured
0
reply
X

Quick Reply

Attached files
Write a reply...
Reply
new posts
Back
to top
Latest
My Feed

See more of what you like on
The Student Room

You can personalise what you see on TSR. Tell us a little about yourself to get started.

Personalise

Current uni students - are you thinking of dropping out of university?

Yes, I'm seriously considering dropping out (170)
14.58%
I'm not sure (54)
4.63%
No, I'm going to stick it out for now (343)
29.42%
I have already dropped out (35)
3%
I'm not a current university student (564)
48.37%

Watched Threads

View All