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Chemistry: Post your doubts here!

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Can someone explain wht is meant by
34 Which statements correctly describe an effect of a rise in temperature on a gas-phase reaction?
1 More particles now have energies greater than the activation energy.
2 The energy distribution profile changes with more particles having the most probable energy.
3 The activation energy of the reaction is decreased.
The one marked in red ik the answer is 1 but I want to understand 2 plzz help
 
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Ammonia is made by the Haber process. The reactants are nitrogen and hydrogen.
N2(g) + 3H2(g) 2NH3(g) ∆H –ve
What will increase the rate of the forward reaction?
A adding argon to the mixture but keeping the total volume constant
B decreasing the temperature
C increasing the total pressure by reducing the total volume at constant temperature
D removing ammonia as it is made but keeping the total volume of the mixture the same
And these one B and C both seem correct ?!
 
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9701/12/O/N/15 Q-39
I am not able to understand how to figure out whether one or many products are formed?
 

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The energy distribution profile changes with more particles having the most probable energy.

Energy distribution profile refers to the profile showing the ethalpy change of a reaction and Activation energy of the reaction ...increasing the temperature will not effect it both will remain the same ......the statement is a bit confusing though.
 
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Can someone explain wht is meant by
34 Which statements correctly describe an effect of a rise in temperature on a gas-phase reaction?
1 More particles now have energies greater than the activation energy.
2 The energy distribution profile changes with more particles having the most probable energy.
3 The activation energy of the reaction is decreased.
The one marked in red ik the answer is 1 but I want to understand 2 plzz help
Capture.JPG

The 'most probable energies' at a specific temperatures are the respective peaks
When temperature increases, the peak is lowered, thus less particles will have the most probable energy
 
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Ammonia is made by the Haber process. The reactants are nitrogen and hydrogen.
N2(g) + 3H2(g) 2NH3(g) ∆H –ve
What will increase the rate of the forward reaction?
A adding argon to the mixture but keeping the total volume constant
B decreasing the temperature
C increasing the total pressure by reducing the total volume at constant temperature
D removing ammonia as it is made but keeping the total volume of the mixture the same
And these one B and C both seem correct ?!


The answer is B because the forward reaction is exothermic and a decrease in temperature will favor the forward reaction. if there is an increase in temperature it will favor the reverse reaction which is endothermic.
 
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coniine is the major constituent of the poison ‘oil of hemlock’
Connine can be synthesised by reacting ammonia with a dibromo compound, X
Q28
9701/12/mj/12
What is the name of compound ?
A 1,1-dibromo-2-propylcyclopentane
B 1,2-dibromo-2-propylcyclopentane
C 1,4-dibromooctane
D 1,5-dibromooctane
pls help ;/
 
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In the manufacture of sulfuric acid the reaction 2SO2(g) + O2(g) 2SO3(g) usually takes place at 400 °C and 1 atm pressure. In one industrial plant, it is decided to change the pressure to
20 atm

What will be the consequences of this change
1 increased running costs
2 an increased percentage of sulfur trioxide in the equilibrium mixture
3 the rate of the backward reaction increases

The answer is A which 1,2 and 3 are correct
But how the rate of the backward reaction increases? I thought it should be decreases?
 
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Q-Use of the Data Booklet is relevant to this question. Which sodium compound contains 74.2% by mass of sodium?
A sodium carbonate
B sodium chloride
C sodium hydroxide
D sodium oxide

Anyone?? Answer is D but I can't figure out why :/
 
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Q-Use of the Data Booklet is relevant to this question. Which sodium compound contains 74.2% by mass of sodium?
A sodium carbonate
B sodium chloride
C sodium hydroxide
D sodium oxide

Anyone?? Answer is D but I can't figure out why :/

(23*2)/((23*2)+16)*100=74.2%
In sodium oxide formula is Na2O
 
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