# A2 chemistry URGENT HELP

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#1
Hi guys, I need your help. I can't figure out bow to do this Q:
200 moles of ammonia and 600 moles of oxygen are placed in a reactor at 600 K and a pressure of 500 KPa. At equilibrium, 100 moles of nitrogen ii oxide have formed.
Calculate a value for the equilibrium constant, Kp, including units, for this equilibrium. give your answer to an appropriate number of significant figures.
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4 weeks ago
#2
Follow the steps as for any Kp calculation. Start with a balanced equation - clearly the reaction does not only produce NO, it also produces water. At 600K water will be a gas so is included in writing an expression for Kp. From the balanced equation you can work out the actual number of moles of water produced (use the ratio of NO to H2O). Work out the partial pressures for each gas (no. of mol of each gas divided by total no. of mol of gas, answer multiplied by 500 kPa). Substitute partial pressures into expression for Kp, remember to raise each to the appropriate power as per your balanced equation. Plug into calculator. Determine units from Kp expression.
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#3
(Original post by Crunch_chemistry)
Follow the steps as for any Kp calculation. Start with a balanced equation - clearly the reaction does not only produce NO, it also produces water. At 600K water will be a gas so is included in writing an expression for Kp. From the balanced equation you can work out the actual number of moles of water produced (use the ratio of NO to H2O). Work out the partial pressures for each gas (no. of mol of each gas divided by total no. of mol of gas, answer multiplied by 500 kPa). Substitute partial pressures into expression for Kp, remember to raise each to the appropriate power as per your balanced equation. Plug into calculator. Determine units from Kp expression.
thank you sooo much Crunch_chemistry
1
4 weeks ago
#4
(Original post by Biochemphy Hope)
Hi guys, I need your help. I can't figure out bow to do this Q:
200 moles of ammonia and 600 moles of oxygen are placed in a reactor at 600 K and a pressure of 500 KPa. At equilibrium, 100 moles of nitrogen ii oxide have formed.
Calculate a value for the equilibrium constant, Kp, including units, for this equilibrium. give your answer to an appropriate number of significant figures.
Use pv=nrt
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#5
(Original post by hello9612)
Use pv=nrt
I will try both the method and will let you know by today evening
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#6
(Original post by Crunch_chemistry)
Follow the steps as for any Kp calculation. Start with a balanced equation - clearly the reaction does not only produce NO, it also produces water. At 600K water will be a gas so is included in writing an expression for Kp. From the balanced equation you can work out the actual number of moles of water produced (use the ratio of NO to H2O). Work out the partial pressures for each gas (no. of mol of each gas divided by total no. of mol of gas, answer multiplied by 500 kPa). Substitute partial pressures into expression for Kp, remember to raise each to the appropriate power as per your balanced equation. Plug into calculator. Determine units from Kp expression.
Hi Crunch_chemistry, I've got an answer of 4.36x10 ^-3 KPa. for the mol of water I've got 150 mol. Is it right?
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#7
(Original post by Crunch_chemistry)
Follow the steps as for any Kp calculation. Start with a balanced equation - clearly the reaction does not only produce NO, it also produces water. At 600K water will be a gas so is included in writing an expression for Kp. From the balanced equation you can work out the actual number of moles of water produced (use the ratio of NO to H2O). Work out the partial pressures for each gas (no. of mol of each gas divided by total no. of mol of gas, answer multiplied by 500 kPa). Substitute partial pressures into expression for Kp, remember to raise each to the appropriate power as per your balanced equation. Plug into calculator. Determine units from Kp expression.
I do well in these questions, I will get a very good predicted grade. So pls Crunch_chemistry can you help me?
I also need help with this last Q

A sample of phosphorus (v) chloride, PCl^5, is heated in a closed system with volume 12.0 dm^3. The mixture reaches an equilibrium described by the following equation: PCl^5= PCl^3+Cl^2
a) the pressure is increased. Describe and explain the effect on the amount of chlorine present at equilibrium.
b) At 520K, the Kc value is 0.202 dm^3 mol^-1.
the equilibrium amount of Cl^2 is found to be 0.0900 mol.
Calculate the amount of PCl^5 present in the 12.0 dm^3 container at equilibrium. Give you answer to an appropriate number of significant figures.
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3 weeks ago
#8
(Original post by Biochemphy Hope)
Hi Crunch_chemistry, I've got an answer of 4.36x10 ^-3 KPa. for the mol of water I've got 150 mol. Is it right?
That's what I got so I hope so! And it is in the right region for a Kp calculation
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