A quick A level Chemistry Question
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The correct answer is Option 1 only.
I would appreciate it if you check whether my thinking is correct to ensure I didnt get this answer by luck.
Option 1
High temperatures favour the forward endothermic process cause one mole of DinitroTetrafluoride to dissociate into two molecules which cause an increase in temperature hence pushing the right hand side mercury limb upwards.
Option 2
The Nitrogen in the right hand vessel sees its average KE increase so does the gas in the left hand vessel. They both exert a similar pressure hence no change in the mercury limb.
Option 3
I cant seem to eliminate this option. Why is it wrong ?
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H2 Chemistry "Gas Laws" topic
Explanation :
Option 1, increasing the temperature favours the forward reaction, and therefore with a greater Kc value at the higher temperature, it means that at equilibrium there would be a greater number of moles of gas in the equilibrium mixture (ie. heating favours the thermal decomposition of each N2O4 molecule into two NO2 molecules). Since no. of moles of gas increases at equilibrium, partial pressure of the equilibrium gas mixture in the left bulb will experience a larger increase, compared to smaller increase in the partial pressure of the nitrogen gas in the right bulb (due to heating), and therefore the mercury level in the right hand limb will rise.
Option 2, because both LHS and RHS of the equation has the same number of moles of gas, hence it doesn't matter if the forward reaction is endo or exo, the no. of moles of gas (in the left bulb) will remain the same at all temperatures. (Although partial pressure of the gas in the left bulb will increase due to heating, bear in mind the nitrogen gas in the other bulb will also experience the same increase in partial pressure due to the heating).
Option 3, "increasing temperature" implies increasing the temperature of the entire experimental setup, ie. both bulbs. Hence, partial pressures of both nitrogen gas samples in both bulbs will increase equally, and the mercury levels remain unchanged in both limbs.
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@UltimaOnline
Just as I suspected. Thank you and much obliged !
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Originally posted by Prozen1:
@UltimaOnline
Just as I suspected. Thank you and much obliged !
@Prozen1, thou art most welcome.