Science

[gokuMI6 1,290]

Those are included - I meant it from the duality of physical and metaphysical.

Ok

 

If anyone wants me to explain Equilibrium and Le Chatelier's principle, do Quote this message with a question, I'm all ears. 

Why don't you just explain  the Le Chatelier's principle using the Haber cycle

[splitterpoint 10,986]

All I see is asdgafsdhgdh now..

[Chronicle 164]

I am totally unfamiliar with the principle, but I do know the definition of equilibrium. Can you please give a summary of what we need to know about these?

 

 

Why don't you just explain  the Le Chatelier's principle using the Haber cycle

Lets start with reversible reactions then work our way up to Le Chatelier's Principle. 

 

A + B  C + D

 

This equation shows a reversible reaction, the reactants (A and B )react to form the products (C and D). the products can react to form the reactants (A and B again.)

 

As [A and B] react their concentration will fall, so the forward reaction will slow down. But as more and more products are made, their concentration rise, therefore the backward reaction will speed up. Sooner or later the forward reaction will go at the very same rate as the backwards one. The system is said to be at Equilibrium.

 

At Equilibrium, both reactions are still happening but there is no overall effect, we call this Dynamic Equilibrium.It simply means the concentrations of the reactants and products have reached a balance and wont change. Another important fact is that Equilibrium is only reached if the reversible reaction takes place in a closed system.

 

Lastly before we go onto Le Chatelier's principle. 

 

Reversible reactions can be Endothermic or Exothermic, when you solve a question about Equilibrium, you must identify whether it's Exothermic or Endothermic. I use the mnemonic "BMX" , Bond Making Exo. Therefore breaking bonds has to be Endothermic. Example: 

 

hydrated copper sulfate (blue)  anhydrous copper sulfate (white) + water

 

Anhydrous means without water, hydrated just means with water.

 

This is the thermal decomposition of hydrated copper sulfate. If we heat the blue hydrated copper sulfate crystals, it drives the water off and leaves white anhydrous copper sulfate powder. This is the Endothermic direction as we are breaking the bonds by putting in heat. If we add a couple of drops of water to the white powder, we will get the blue crystals back again as shown in the equation. This is the Exothermic direction as we are making bonds. 

 

Le Chatelier's Principle is the idea that If a dynamic equilibrium is disturbed by changing the conditions, the position of equilibrium moves to counteract the change.This can be utilized to foresee the impact of any changes you make to the reaction system. 

 

Changes to the Temperature: 

 

Increasing the Temperature:

 

You have to know whether heat is given out or retained amid the reaction. Assuming that our forward reaction is exothermic (heat is developed):

 

3H2 + N2  2NH3.

 

The forward reaction is Exothermic, we are making bonds. (BMX)

 

Lets go back to Le Chatelier's Principle, the position of Equilibrium will move in a way to counteract the change. In this case, the position of Equilibrium will move so that temperature is reduced again. But how does it cool down? Well to cool down, the reaction has to absorb the "excess" heat that has been put in. If Exothermic direction gives out heat, what absorbs heat? Endothermic direction. In this case we are looking at the backward which absorbs heat. Therefore the position of Equilibrium moves to the left to try and decrease the temperature. You'll now get more products for the endothermic reaction (N2 + 3H2) and fewer products for the Exothermic reaction (2NH3). If you aim to make more 2NH3, then increasing the temperature on a reversible reaction where the forward reaction is Exothermic, bad Idea. 

 

Decrease Temperature: 

 

This time, Equilibrium will move in a way that temperature increases again. The reaction tends to heat itself back up again to the original temperature. It does this by favouring the Exothermic reaction.Therefore the position of Equilibrium will move the right, the Exothermic direction to produce more heat. This means you'll get more products for the Exothermic reaction and fewer products for the Endothermic reaction. 

 

Summary for Temperature: 

 

If you increase the temperature of a system (in dynamic equilibrium), equilibrium will move to endothermic side to compensate. The system counteracts the change of increasing the temperature by decreasing it via absorption. 

 

If you decrease the temperature of a system (in dynamic equilibrium), equilibrium will move and favour the exothermic side to compensate. The system counteracts the change you made (decreasing the temperature) by increasing the temperature (produce more heat).

 

 

Changes to Concentration: 

 

3H2 + N2  2NH3

 

The reason for choosing this equation for all of the examples is because further down I will need an equation that has the same number of molecules in both sides.

 

If we change the concentration of either the reactants or the products, the system will no longer be at Equilibrium, so the system tries to bring itself back at Equilibrium. 

 

Increase the Concentration of reactants:

 

The system is no longer in Equilibrium, In this case the position of equilibrium will move to the right so that the concentration of N2 + 3H2 decreases again. The position of equilibrium moves to the right to produce more products, the concentration of all substances will change until equilibrium is reached again. 

 

Decrease the Concentration of products:

 

If the concentration of 1 or both of the products decreases, Equilibrium will move so that the concentration of one or both of the products are increased again. Because we decreased the concentration of the products, the system is no longer at Equilibrium. More N2 + 3H2 will react to form 2NH3 until equilibrium is reached again, vice versa if we increase the concentration of products. 

 

Summary for Concentration: 

 

If you increase the concentration of the reactants, the system tries to decrease it by making more products.

 

If you decrease the concentration of products, the system tries to increase it by reducing the amount of reactants, vice versa if we increase the concentration of products.

 

Changes of Pressure: 

 

Increasing the Pressure: 

 

Changing the pressure only affects Equilibrium involving gas molecules, such as the Haber process, acid reactions... etc

 

3H2 + N2  2NH3

 

According to Le Chatelier's Principle, the position of equilibrium will move so that the pressure is reduced again, this is done when Equilibrium moves in the direction where there are fewer molecules. Increasing the pressure on a gas reaction shifts the position of equilibrium towards the side with fewer molecules. There are 4 molecules on the left, but only 2 on the right. Therefore, the Equilibrium will shift to the right, to produce more NH3.

 

Decreasing the pressure: 

 

Similarly, Equilibrium will move in such a way that the pressure increases again. In this case decreasing the pressure will make Equilibrium move to the direction with more molecules of gas, in this case the backwards reaction, to produce more N2 + 3H2. 

 

What if there's the same number of molecules on both sides of the reaction?

 

In that case, increasing the pressure has no effect on the position of Equilibrium, you simply have the same number of molecules on both sides, Equilibrium can't move to reduce the pressure again. 

 

Summary for Pressure: 

 

Pressure only affects an Equilibrium involving gases

If you increase pressure, Equilibrium tries to reduce it by moving in the direction where there are fewer molecules of gas

If you decrease the pressure, Equilibrium tries to increase it by moving in the direction where there are more molecules of gas. 

 

Explaining Le Chatelier's Principle in terms of the Haber Process:

 

The Haber process is an important industrial technique, it produces ammonia which is used to make fertilizers. 

 

Here's the reaction used: 

 

N2(g) + 3H2(g)  2NH3(g) 

 

Luckily, the reaction is reversible. There's a compromise to be made and the industry uses Le Chatelier's Principle to maximize the yield of a reaction, they seek to improve the atom economy of the reaction to make more useful products. Using "BMX" we know that the forward reaction of this process is Exothermic. Let's start by increasing the temperature, well increasing the temperature causes Equilibrium to shift to the endothermic side, the wrong way which is away from ammonia and towards nitrogen and hydrogen. We don't want this, we want more ammonia, so the yield of ammonia would be greater at lower temperatures. But this means a slower rate of reaction, Equilibrium is reached more slowly. 

 

Using Le Chatelier's Principle, a higher pressure shifts the position of equilibrium towards the products, because there are 4 molecules on the left hand side and two molecules on the right as shown in the equation. Increasing the pressure maximizes the percentage yield, but increases the rate of reaction rather than decrease it. However there is a downside to increasing the pressure, its very expensive and dangerous to build and maintain. 

 

Lastly, adding a catalyst. Catalysts make no difference to the position of Equilibrium, this is because a Catalyst speeds up the reaction without being used up in the overall reaction, it simply isn't part of the reaction and is not included in the reaction equation. For the haber process, an iron catalyst is usually used. And a catalyst increases the rate of reaction by providing a shorter reaction pathway for the reactants, this can be shown on a reaction profile as it lowers the activation energy needed for the reactants to react. The catalyst doesn't affect the relative rates of both reactions. It just helps reach dynamic Equilibrium faster. 

 

I wasn't allowed to post pictures for some reason, so I used equations, although I believe with pictures it would have been much easier. Apologies...

Edited July 4, 2018 by Chronicle

[Violated 34]

Lol Ghosty Le Chatelier's principle is A level Chemistry. The Haber cycle is A2 chemistry, so I don't suppose you will know about it.

Edited July 4, 2018 by Violated

[GorgoBlesk 831]

CH4

C2H5

 

and the most intresting and unique thing eve is H2O

Best chemicals are:

 

CH3-CH2-OH

H2SO4

HNO3

NaOH

KOH

HCl

Liquid N2

[Condensation 478]

 

Lets start with reversible reactions then work our way up to Le Chatelier's Principle. 

 

A + B  C + D

 

This equation shows a reversible reaction, the reactants (A and B )react to form the products (C and D). the products can react to form the reactants (A and B again.)

 

As [A and B] react their concentration will fall, so the forward reaction will slow down. But as more and more products are made, their concentration rise, therefore the backward reaction will speed up. Sooner or later the forward reaction will go at the very same rate as the backwards one. The system is said to be at Equilibrium.

 

At Equilibrium, both reactions are still happening but there is no overall effect, we call this Dynamic Equilibrium.It simply means the concentrations of the reactants and products have reached a balance and wont change. Another important fact is that Equilibrium is only reached if the reversible reaction takes place in a closed system.

 

Lastly before we go onto Le Chatelier's principle. 

 

Reversible reactions can be Endothermic or Exothermic, when you solve a question about Equilibrium, you must identify whether it's Exothermic or Endothermic. I use the mnemonic "BMX" , Bond Making Exo. Therefore breaking bonds has to be Endothermic. Example: 

 

hydrated copper sulfate (blue)  anhydrous copper sulfate (white) + water

 

Anhydrous means without water, hydrated just means with water.

 

This is the thermal decomposition of hydrated copper sulfate. If we heat the blue hydrated copper sulfate crystals, it drives the water off and leaves white anhydrous copper sulfate powder. This is the Endothermic direction as we are breaking the bonds by putting in heat. If we add a couple of drops of water to the white powder, we will get the blue crystals back again as shown in the equation. This is the Exothermic direction as we are making bonds. 

 

Le Chatelier's Principle is the idea that If a dynamic equilibrium is disturbed by changing the conditions, the position of equilibrium moves to counteract the change.This can be utilized to foresee the impact of any changes you make to the reaction system. 

 

Changes to the Temperature: 

 

Increasing the Temperature:

 

You have to know whether heat is given out or retained amid the reaction. Assuming that our forward reaction is exothermic (heat is developed):

 

3H2 + N2  2NH3.

 

The forward reaction is Exothermic, we are making bonds. (BMX)

 

Lets go back to Le Chatelier's Principle, the position of Equilibrium will move in a way to counteract the change. In this case, the position of Equilibrium will move so that temperature is reduced again. But how does it cool down? Well to cool down, the reaction has to absorb the "excess" heat that has been put in. If Exothermic direction gives out heat, what absorbs heat? Endothermic direction. In this case we are looking at the backward which absorbs heat. Therefore the position of Equilibrium moves to the left to try and decrease the temperature. You'll now get more products for the endothermic reaction (N2 + 3H2) and fewer products for the Exothermic reaction (2NH3). If you aim to make more 2NH3, then increasing the temperature on a reversible reaction where the forward reaction is Exothermic, bad Idea. 

 

Decrease Temperature: 

 

This time, Equilibrium will move in a way that temperature increases again. The reaction tends to heat itself back up again to the original temperature. It does this by favouring the Exothermic reaction.Therefore the position of Equilibrium will move the right, the Exothermic direction to produce more heat. This means you'll get more products for the Exothermic reaction and fewer products for the Endothermic reaction. 

 

Summary for Temperature: 

 

If you increase the temperature of a system (in dynamic equilibrium), equilibrium will move to endothermic side to compensate. The system counteracts the change of increasing the temperature by decreasing it via absorption. 

 

If you decrease the temperature of a system (in dynamic equilibrium), equilibrium will move and favour the exothermic side to compensate. The system counteracts the change you made (decreasing the temperature) by increasing the temperature (produce more heat).

 

 

Changes to Concentration: 

 

3H2 + N2  2NH3

 

The reason for choosing this equation for all of the examples is because further down I will need an equation that has the same number of molecules in both sides.

 

If we change the concentration of either the reactants or the products, the system will no longer be at Equilibrium, so the system tries to bring itself back at Equilibrium. 

 

Increase the Concentration of reactants:

 

The system is no longer in Equilibrium, In this case the position of equilibrium will move to the right so that the concentration of N2 + 3H2 decreases again. The position of equilibrium moves to the right to produce more products, the concentration of all substances will change until equilibrium is reached again. 

 

Decrease the Concentration of products:

 

If the concentration of 1 or both of the products decreases, Equilibrium will move so that the concentration of one or both of the products are increased again. Because we decreased the concentration of the products, the system is no longer at Equilibrium. More N2 + 3H2 will react to form 2NH3 until equilibrium is reached again, vice versa if we increase the concentration of products. 

 

Summary for Concentration: 

 

If you increase the concentration of the reactants, the system tries to decrease it by making more products.

 

If you decrease the concentration of products, the system tries to increase it by reducing the amount of reactants, vice versa if we increase the concentration of products.

 

Changes of Pressure: 

 

Increasing the Pressure: 

 

Changing the pressure only affects Equilibrium involving gas molecules, such as the Haber process, acid reactions... etc

 

3H2 + N2  2NH3

 

According to Le Chatelier's Principle, the position of equilibrium will move so that the pressure is reduced again, this is done when Equilibrium moves in the direction where there are fewer molecules. Increasing the pressure on a gas reaction shifts the position of equilibrium towards the side with fewer molecules. There are 4 molecules on the left, but only 2 on the right. Therefore, the Equilibrium will shift to the right, to produce more NH3.

 

Decreasing the pressure: 

 

Similarly, Equilibrium will move in such a way that the pressure increases again. In this case decreasing the pressure will make Equilibrium move to the direction with more molecules of gas, in this case the backwards reaction, to produce more N2 + 3H2. 

 

What if there's the same number of molecules on both sides of the reaction?

 

In that case, increasing the pressure has no effect on the position of Equilibrium, you simply have the same number of molecules on both sides, Equilibrium can't move to reduce the pressure again. 

 

Summary for Pressure: 

 

Pressure only affects an Equilibrium involving gases

If you increase pressure, Equilibrium tries to reduce it by moving in the direction where there are fewer molecules of gas

If you decrease the pressure, Equilibrium tries to increase it by moving in the direction where there are more molecules of gas. 

 

Explaining Le Chatelier's Principle in terms of the Haber Process:

 

The Haber process is an important industrial technique, it produces ammonia which is used to make fertilizers. 

 

Here's the reaction used: 

 

N2(g) + 3H2(g)  2NH3(g) 

 

Luckily, the reaction is reversible. There's a compromise to be made and the industry uses Le Chatelier's Principle to maximize the yield of a reaction, they seek to improve the atom economy of the reaction to make more useful products. Using "BMX" we know that the forward reaction of this process is Exothermic. Let's start by increasing the temperature, well increasing the temperature causes Equilibrium to shift to the endothermic side, the wrong way which is away from ammonia and towards nitrogen and hydrogen. We don't want this, we want more ammonia, so the yield of ammonia would be greater at lower temperatures. But this means a slower rate of reaction, Equilibrium is reached more slowly. 

 

Using Le Chatelier's Principle, a higher pressure shifts the position of equilibrium towards the products, because there are 4 molecules on the left hand side and two molecules on the right as shown in the equation. Increasing the pressure maximizes the percentage yield, but increases the rate of reaction rather than decrease it. However there is a downside to increasing the pressure, its very expensive and dangerous to build and maintain. 

 

Lastly, adding a catalyst. Catalysts make no difference to the position of Equilibrium, this is because a Catalyst speeds up the reaction without being used up in the overall reaction, it simply isn't part of the reaction and is not included in the reaction equation. For the haber process, an iron catalyst is usually used. And a catalyst increases the rate of reaction by providing a shorter reaction pathway for the reactants, this can be shown on a reaction profile as it lowers the activation energy needed for the reactants to react. The catalyst doesn't affect the relative rates of both reactions. It just helps reach dynamic Equilibrium faster. 

 

I wasn't allowed to post pictures for some reason, so I used equations, although I believe with pictures it would have been much easier. Apologies...

 

Thank You I'm so happy I didn't need to post that! :D :ph34r:

[Condensation 478]

Most Toxic Substance Known to Man:Botulinum Toxin :ph34r:

 

Science.

[Chronicle 164]

Does anyone want anything on electromagnetic induction? (Physics) 

[monkeyburn 13,566]

Anti-gravity...Can't get enough!  :wub:

[gokuMI6 1,290]

Best chemicals are:

 

CH3-CH2-OH

H2SO4

HNO3

NaOH

KOH

HCl

Liquid N2

everything is perfect  :D

well and for the record you are missing some very class of chemicals

Espceially

our Co-ordinations complexes and some organic groups  :)

I am too lazy to type them all 

Edited July 6, 2018 by gokuMI6

[Condensation 478]

Oh, And Everyone gimme suggestions for polls :P

Does anyone want anything on electromagnetic induction? (Physics) 

Sure.

[Condensation 478]

Did anyone know that the earth is flat? :ph34r:

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Jk.

[Chronicle 164]

Did anyone know that the earth is flat? :ph34r:

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Jk.

Boy, don't get me started! I joined a facebook group 2-3 months ago about the flat earth, where people constantly argue whether its flat or round. Its round of course, as the scientific mind knows. Duh. Anyhow, I wrote this 3 paragraph explanation to why I think the earth is round and not flat. Would you like me to post it? Its my own work and is not plagiarized 

[ThirdOnion 4,898]

Boy, don't get me started! I joined a facebook group 2-3 months ago about the flat earth, where people constantly argue whether its flat or round. Its round of course, as the scientific mind knows. Duh.

The reason, I feel, that such drawn out arguments take place is because neither side has a strong conceptual framework to build their argument around. People who can actually properly argue about science tend not to engage in such conversations.

[Chronicle 164]

The reason, I feel, that such drawn out arguments take place is because neither side has a strong conceptual framework to build their argument around. People who can actually properly argue about science tend not to engage in such conversations.

Well its questionable. Contingent upon the point, I find that having a debate improves one's skills and knowledge of the topic they are having a debate about. It also assists them with developing an urban and political personality. You said it yourself, "neither side has a strong conceptual framework". Well this is why people have debates in the first place, they start at the bottom, they work their way up by learning more from past experience (previous arguments).  

 

Once again, It depends on the topic. Despite that as of now we maintain oodles of proof that the earth is round and not level, we appear to require even more evidence because maths and science alone aren't looking auspicious (to flat-earthers). The importance of having a debate is irrefutable.

[QuicKK 975]

What is a blackhole? :o

[ThirdOnion 4,898]

Once again, It depends on the topic. Despite that as of now we maintain oodles of proof that the earth is round and not level, we appear to require even more evidence because maths and science alone aren't looking auspicious (to flat-earthers). The importance of having a debate is irrefutable.

This is all true. But my point was that despite oodles of evidence people who argue with flat-earthers rarely present it in a convincing and logical fashion. Sometimes it is fun to pretend to be a flat-earther and see how easily it is to refute weak arguments built on substantial evidence.

[Chronicle 164]

This is all true. But my point was that despite oodles of evidence people who argue with flat-earthers rarely present it in a convincing and logical fashion. Sometimes it is fun to pretend to be a flat-earther and see how easily it is to refute weak arguments built on substantial evidence.

People who argue with flat-earthers? Just to be clear, are you saying that flat-earthers are far more convincing thus far? That I disagree on, but in a way pretending to be a flat-earther and refute the existence of gravity, enjoyable to an extent. 

[ThirdOnion 4,898]

People who argue with flat-earthers? Just to be clear, are you saying that flat-earthers are far more convincing thus far?

No, I'm saying that the people who argue with flat-earthers tend to use the same dodgy logic that they do.

[Chronicle 164]

No, I'm saying that the people who argue with flat-earthers tend to use the same dodgy logic that they do.

Ohhh u mean science!! Right, gotcha! 

[Condensation 478]

What Micro-organism would you be? :ph34r:

What is a blackhole? :o

a region of space having a gravitational field so intense that no matter or radiation can escape.

[Condensation 478]

Hey Do Aliens Count as Animals? As in Animals In Space? :ph34r:

[GorgoBlesk 831]

Hey Do Aliens Count as Animals? As in Animals In Space? :ph34r:

If they are stupid, yes. If they are intelligent, kill them ASAP!

[QuicKK 975]

What Micro-organism would you be? :ph34r:

protozoa

Edited July 20, 2018 by QuicKK

[Condensation 478]

Earth is Flat?

Edited July 21, 2018 by Condensation