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AP Chemistry Exam

PeacefulChaos
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5/2/2014 10:11:43 PM
Posted: 2 years ago
Hello, everyone. On Monday I'll be having the AP Chemistry Exam, and so I made this thread to ask some questions and better understand concepts. Hopefully all goes well. If anyone has ever taken this exam, then I'd also greatly appreciate it if you could give me tips or pointers on where specifically to study.

My first question is concerned with ionization energy (specifically, the first one). Would Ga (Gallium) have a lower ionization energy than Ca (Calcium)? Would Indium have a lower ionization energy than Strontium? And so on. Although it goes against the periodic trend of ionization energy, it makes sense that it would require more energy to remove an electron from a fully filled "s" orbital than a "p" orbital. While we're still on the topic of trend inconsistencies, would Phosphorous have a higher ionization energy than Sulfur because Phosphorous has half of its valence electron shell filled?

I'll update this with more questions as time goes on.
PeacefulChaos
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5/2/2014 10:22:51 PM
Posted: 2 years ago
Generally speaking, which of the following is endothermic and which is exothermic?

Breaking bonds vs. Forming bonds

Does this depend entirely upon how stable the molecule is? For example, ATP is relatively unstable, and so breaking it requires very little energy, but releases quite a lot of energy, thus making it an exothermic process; however, with more stable molecules, such as NaCl, wouldn't breaking bonds be an endothermic process, while the formation of bonds would be an exothermic one?
PeacefulChaos
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5/2/2014 10:36:21 PM
Posted: 2 years ago
Here is a question from a previously released AP Exam:

1. Equilibrium Vapor Pressure @ 20 degrees C (torr)

CH3OH: 92
C2H6O2: 0.06

Based on the data in the table above, which of the following liquid substances has the weakest intermolecular forces?

C. CH3OH
D. C2H6O2

(I excluded A & B from the choices and the chart. Apparently the answer is C, but I don't know why.)
Mhykiel
Posts: 5,987
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5/2/2014 11:41:14 PM
Posted: 2 years ago
At 5/2/2014 10:36:21 PM, PeacefulChaos wrote:
Here is a question from a previously released AP Exam:

1. Equilibrium Vapor Pressure @ 20 degrees C (torr)

CH3OH: 92
C2H6O2: 0.06

Based on the data in the table above, which of the following liquid substances has the weakest intermolecular forces?

C. CH3OH
D. C2H6O2

(I excluded A & B from the choices and the chart. Apparently the answer is C, but I don't know why.)

The weaker the force between molecules the easier it is for them to transition into a gas phase. Because more molecules rise from the liquid they are a denser gas and have higher pressure.

Reading all your posts. I think you already know these answers.
Enji
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5/3/2014 12:04:36 AM
Posted: 2 years ago
At 5/2/2014 10:22:51 PM, PeacefulChaos wrote:
Generally speaking, which of the following is endothermic and which is exothermic?

Breaking bonds vs. Forming bonds

Does this depend entirely upon how stable the molecule is? For example, ATP is relatively unstable, and so breaking it requires very little energy, but releases quite a lot of energy, thus making it an exothermic process; however, with more stable molecules, such as NaCl, wouldn't breaking bonds be an endothermic process, while the formation of bonds would be an exothermic one?

The activation energy (I'm guessing this was a defined term at some point in your course and it should be in your textbook somewhere) is the minimum energy it takes for a reaction to start -- this is the energy needed to break the existing bonds. Breaking bonds always requires energy and so breaking bonds is always endothermic. Energy is released when new bonds are formed so forming bonds is always exothermic. A reaction is exothermic if the energy released in the forming of new bonds is greater than the energy needed to break the existing bonds.

At 5/2/2014 10:36:21 PM, PeacefulChaos wrote:
Here is a question from a previously released AP Exam:

1. Equilibrium Vapor Pressure @ 20 degrees C (torr)

CH3OH: 92
C2H6O2: 0.06

Based on the data in the table above, which of the following liquid substances has the weakest intermolecular forces?

C. CH3OH
D. C2H6O2

(I excluded A & B from the choices and the chart. Apparently the answer is C, but I don't know why.)

The equilibrium vapour pressure is the pressure of a vapour in equilibrium with its non-vapour phases at a given temperature, which essentially means it's a measure of how easily something evaporates. Substances with stronger intermolecular forces require more energy for a molecule to escape and hence evaporate less easily so they will have lower equilibrium vapour pressures. Presumably, CH3OH had the highest pressure of the bunch.
PeacefulChaos
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5/3/2014 12:08:30 PM
Posted: 2 years ago
At 5/2/2014 11:41:14 PM, Mhykiel wrote:
At 5/2/2014 10:36:21 PM, PeacefulChaos wrote:
Here is a question from a previously released AP Exam:

1. Equilibrium Vapor Pressure @ 20 degrees C (torr)

CH3OH: 92
C2H6O2: 0.06

Based on the data in the table above, which of the following liquid substances has the weakest intermolecular forces?

C. CH3OH
D. C2H6O2

(I excluded A & B from the choices and the chart. Apparently the answer is C, but I don't know why.)

The weaker the force between molecules the easier it is for them to transition into a gas phase. Because more molecules rise from the liquid they are a denser gas and have higher pressure.

Reading all your posts. I think you already know these answers.

Thanks for the explanation.

I just posted some simple questions first to see if this thread would get any responses and to make sure that my reasoning was correct behind the answers. This question I was honestly confused on, though.
Mhykiel
Posts: 5,987
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5/3/2014 1:26:55 PM
Posted: 2 years ago
At 5/2/2014 10:11:43 PM, PeacefulChaos wrote:
Hello, everyone. On Monday I'll be having the AP Chemistry Exam, and so I made this thread to ask some questions and better understand concepts. Hopefully all goes well. If anyone has ever taken this exam, then I'd also greatly appreciate it if you could give me tips or pointers on where specifically to study.

My first question is concerned with ionization energy (specifically, the first one). Would Ga (Gallium) have a lower ionization energy than Ca (Calcium)? Would Indium have a lower ionization energy than Strontium? And so on. Although it goes against the periodic trend of ionization energy, it makes sense that it would require more energy to remove an electron from a fully filled "s" orbital than a "p" orbital. While we're still on the topic of trend inconsistencies, would Phosphorous have a higher ionization energy than Sulfur because Phosphorous has half of its valence electron shell filled?

I'll update this with more questions as time goes on.

Yes, No, Yes. No. With Valence electrons shells that are filled and further from the atomic forces the less energy it needs to ionization energy it needs. The Ionization energy is the difference between forces of the positron in the nucleus against the negatively charged electrons in orbit. When an electron is removed the force of the positrons is now greater among the remaining electrons. Making it harder to remove another. It matter more how close the valence electrons are to the atomic core, not really how many there are.

For more on the vapor equilibrium. It is a cycle. Classic example is you put a 1/3 water in a water bottle. The weak intermolecular force lets them evaporate easy. So the gas fills the chamber. the gas fills till the pressure climbs enough to push the atoms back together and the vapor condenses into liquid. Process repeats keeping water level at same level. Equilibrium. If the atoms have a strong intermolecular force they don't have to push as close together by pressure before that condense.

I'm sure you have tried to google this stuff haven't you?
PeacefulChaos
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5/3/2014 9:05:03 PM
Posted: 2 years ago
At 5/3/2014 1:26:55 PM, Mhykiel wrote:
At 5/2/2014 10:11:43 PM, PeacefulChaos wrote:
Hello, everyone. On Monday I'll be having the AP Chemistry Exam, and so I made this thread to ask some questions and better understand concepts. Hopefully all goes well. If anyone has ever taken this exam, then I'd also greatly appreciate it if you could give me tips or pointers on where specifically to study.

My first question is concerned with ionization energy (specifically, the first one). Would Ga (Gallium) have a lower ionization energy than Ca (Calcium)? Would Indium have a lower ionization energy than Strontium? And so on. Although it goes against the periodic trend of ionization energy, it makes sense that it would require more energy to remove an electron from a fully filled "s" orbital than a "p" orbital. While we're still on the topic of trend inconsistencies, would Phosphorous have a higher ionization energy than Sulfur because Phosphorous has half of its valence electron shell filled?

I'll update this with more questions as time goes on.

Yes, No, Yes. No. With Valence electrons shells that are filled and further from the atomic forces the less energy it needs to ionization energy it needs. The Ionization energy is the difference between forces of the positron in the nucleus against the negatively charged electrons in orbit. When an electron is removed the force of the positrons is now greater among the remaining electrons. Making it harder to remove another. It matter more how close the valence electrons are to the atomic core, not really how many there are.

For more on the vapor equilibrium. It is a cycle. Classic example is you put a 1/3 water in a water bottle. The weak intermolecular force lets them evaporate easy. So the gas fills the chamber. the gas fills till the pressure climbs enough to push the atoms back together and the vapor condenses into liquid. Process repeats keeping water level at same level. Equilibrium. If the atoms have a strong intermolecular force they don't have to push as close together by pressure before that condense.

I'm sure you have tried to google this stuff haven't you?

Google gives varying answers. For example, Google told me that Phosphorous actually does have a higher ionization energy than Sulfur, which you claimed it doesn't.
Mhykiel
Posts: 5,987
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5/3/2014 10:00:54 PM
Posted: 2 years ago
At 5/3/2014 9:05:03 PM, PeacefulChaos wrote:
At 5/3/2014 1:26:55 PM, Mhykiel wrote:
At 5/2/2014 10:11:43 PM, PeacefulChaos wrote:
Hello, everyone. On Monday I'll be having the AP Chemistry Exam, and so I made this thread to ask some questions and better understand concepts. Hopefully all goes well. If anyone has ever taken this exam, then I'd also greatly appreciate it if you could give me tips or pointers on where specifically to study. by

My first question is concerned with ionization energy (specifically, the first one). Would Ga (Gallium) have a lower ionization energy than Ca (Calcium)? Would Indium have a lower ionization energy than Strontium? And so on. Although it goes against the periodic trend of ionization energy, it makes sense that it would require more energy to remove an electron from a fully filled "s" orbital than a "p" orbital. While we're still on the topic of trend inconsistencies, would Phosphorous have a higher ionization energy than Sulfur because Phosphorous has half of its valence electron shell filled?

I'll update this with more questions as time goes on.

Yes, No, Yes. No. With Valence electrons shells that are filled and further from the atomic forces the less energy it needs to ionization energy it needs. The Ionization energy is the difference between forces of the positron in the nucleus against the negatively charged electrons in orbit. When an electron is removed the force of the positrons is now greater among the remaining electrons. Making it harder to remove another. It matter more how close the valence electrons are to the atomic core, not really how many there are.

For more on the vapor equilibrium. It is a cycle. Classic example is you put a 1/3 water in a water bottle. The weak intermolecular force lets them evaporate easy. So the gas fills the chamber. the gas fills till the pressure climbs enough to push the atoms back together and the vapor condenses into liquid. Process repeats keeping water level at same level. Equilibrium. If the atoms have a strong intermolecular force they don't have to push as close together by pressure before that condense.

I'm sure you have tried to google this stuff haven't you?

Google gives varying answers. For example, Google told me that Phosphorous actually does have a higher ionization energy than Sulfur, which you claimed it doesn't.

i said p has a higher ionization then sulphur i was saying no to the reason.
Mhykiel
Posts: 5,987
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5/3/2014 10:06:44 PM
Posted: 2 years ago
At 5/3/2014 10:00:54 PM, Mhykiel wrote:
At 5/3/2014 9:05:03 PM, PeacefulChaos wrote:
At 5/3/2014 1:26:55 PM, Mhykiel wrote:
At 5/2/2014 10:11:43 PM, PeacefulChaos wrote:
Hello, everyone. On Monday I'll be having the AP Chemistry Exam, and so I made this thread to ask some questions and better understand concepts. Hopefully all goes well. If anyone has ever taken this exam, then I'd also greatly appreciate it if you could give me tips or pointers on where specifically to study. byby

My first question is concerned with ionization energy (specifically, the first one). Would Ga (Gallium) have a lower ionization energy than Ca (Calcium)? Would Indium have a lower ionization energy than Strontium? And so on. Although it goes against the periodic trend of ionization energy, it makes sense that it would require more energy to remove an electron from a fully filled "s" orbital than a "p" orbital. While we're still on the topic of trend inconsistencies, would Phosphorous have a higher ionization energy than Sulfur because Phosphorous has half of its valence electron shell filled?

I'll update this with more questions as time goes on.

Yes, No, Yes. No. With Valence electrons shells that are filled and further from the atomic forces the less energy it needs to ionization energy it needs. The Ionization energy is the difference between forces of the positron in the nucleus against the negatively charged electrons in orbit. When an electron is removed the force of the positrons is now greater among the remaining electrons. Making it harder to remove another. It matter more how close the valence electrons are to the atomic core, not really how many there are.

For more on the vapor equilibrium. It is a cycle. Classic example is you put a 1/3 water in a water bottle. The weak intermolecular force lets them evaporate easy. So the gas fills the chamber. the gas fills till the pressure climbs enough to push the atoms back together and the vapor condenses into liquid. Process repeats keeping water level at same level. Equilibrium. If the atoms have a strong intermolecular force they don't have to push as close together by pressure before that condense.

I'm sure you have tried to google this stuff haven't you?

Google gives varying answers. For example, Google told me that Phosphorous actually does have a higher ionization energy than Sulfur, which you claimed it doesn't.

i said p has a higher ionization then sulphur i was saying no to the reason.

i thought this was becuase sulphur has one more proton and one proton can hold more than the one electron it gains. so the strength of the protons is more than the gain in elsctrons. why it takes more to eject a sulphur electron than a phosphorous
PeacefulChaos
Posts: 2,612
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5/3/2014 10:16:25 PM
Posted: 2 years ago
At 5/3/2014 10:06:44 PM, Mhykiel wrote:
At 5/3/2014 10:00:54 PM, Mhykiel wrote:
At 5/3/2014 9:05:03 PM, PeacefulChaos wrote:
At 5/3/2014 1:26:55 PM, Mhykiel wrote:
At 5/2/2014 10:11:43 PM, PeacefulChaos wrote:
Hello, everyone. On Monday I'll be having the AP Chemistry Exam, and so I made this thread to ask some questions and better understand concepts. Hopefully all goes well. If anyone has ever taken this exam, then I'd also greatly appreciate it if you could give me tips or pointers on where specifically to study. byby

My first question is concerned with ionization energy (specifically, the first one). Would Ga (Gallium) have a lower ionization energy than Ca (Calcium)? Would Indium have a lower ionization energy than Strontium? And so on. Although it goes against the periodic trend of ionization energy, it makes sense that it would require more energy to remove an electron from a fully filled "s" orbital than a "p" orbital. While we're still on the topic of trend inconsistencies, would Phosphorous have a higher ionization energy than Sulfur because Phosphorous has half of its valence electron shell filled?

I'll update this with more questions as time goes on.

Yes, No, Yes. No. With Valence electrons shells that are filled and further from the atomic forces the less energy it needs to ionization energy it needs. The Ionization energy is the difference between forces of the positron in the nucleus against the negatively charged electrons in orbit. When an electron is removed the force of the positrons is now greater among the remaining electrons. Making it harder to remove another. It matter more how close the valence electrons are to the atomic core, not really how many there are.

For more on the vapor equilibrium. It is a cycle. Classic example is you put a 1/3 water in a water bottle. The weak intermolecular force lets them evaporate easy. So the gas fills the chamber. the gas fills till the pressure climbs enough to push the atoms back together and the vapor condenses into liquid. Process repeats keeping water level at same level. Equilibrium. If the atoms have a strong intermolecular force they don't have to push as close together by pressure before that condense.

I'm sure you have tried to google this stuff haven't you?

Google gives varying answers. For example, Google told me that Phosphorous actually does have a higher ionization energy than Sulfur, which you claimed it doesn't.

i said p has a higher ionization then sulphur i was saying no to the reason.

i thought this was becuase sulphur has one more proton and one proton can hold more than the one electron it gains. so the strength of the protons is more than the gain in elsctrons. why it takes more to eject a sulphur electron than a phosphorous

If it takes more to eject a sulphur electron that means "S" would have the higher ionization energy, which it doesn't.
Mhykiel
Posts: 5,987
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5/3/2014 10:25:15 PM
Posted: 2 years ago
At 5/3/2014 10:16:25 PM, PeacefulChaos wrote:
At 5/3/2014 10:06:44 PM, Mhykiel wrote:
At 5/3/2014 10:00:54 PM, Mhykiel wrote:
At 5/3/2014 9:05:03 PM, PeacefulChaos wrote:
At 5/3/2014 1:26:55 PM, Mhykiel wrote:
At 5/2/2014 10:11:43 PM, PeacefulChaos wrote:
Hello, everyone. On Monday I'll be having the AP Chemistry Exam, and so I made this thread to ask some questions and better understand concepts. Hopefully all goes well. If anyone has ever taken this exam, then I'd also greatly appreciate it if you could give me tips or pointers on where specifically to study. byby

My first question is concerned with ionization energy (specifically, the first one). Would Ga (Gallium) have a lower ionization energy than Ca (Calcium)? Would Indium have a lower ionization energy than Strontium? And so on. Although it goes against the periodic trend of ionization energy, it makes sense that it would require more energy to remove an electron from a fully filled "s" orbital than a "p" orbital. While we're still on the topic of trend inconsistencies, would Phosphorous have a higher ionization energy than Sulfur because Phosphorous has half of its valence electron shell filled?

I'll update this with more questions as time goes on.

Yes, No, Yes. No. With Valence electrons shells that are filled and further from the atomic forces the less energy it needs to ionization energy it needs. The Ionization energy is the difference between forces of the positron in the nucleus against the negatively charged electrons in orbit. When an electron is removed the force of the positrons is now greater among the remaining electrons. Making it harder to remove another. It matter more how close the valence electrons are to the atomic core, not really how many there are.

For more on the vapor equilibrium. It is a cycle. Classic example is you put a 1/3 water in a water bottle. The weak intermolecular force lets them evaporate easy. So the gas fills the chamber. the gas fills till the pressure climbs enough to push the atoms back together and the vapor condenses into liquid. Process repeats keeping water level at same level. Equilibrium. If the atoms have a strong intermolecular force they don't have to push as close together by pressure before that condense.

I'm sure you have tried to google this stuff haven't you?

Google gives varying answers. For example, Google told me that Phosphorous actually does have a higher ionization energy than Sulfur, which you claimed it doesn't.

i said p has a higher ionization then sulphur i was saying no to the reason.

i thought this was becuase sulphur has one more proton and one proton can hold more than the one electron it gains. so the strength of the protons is more than the gain in elsctrons. why it takes more to eject a sulphur electron than a phosphorous

If it takes more to eject a sulfur electron that means "S" would have the higher ionization energy, which it doesn't.

I'm sorry I'm on my computer now. You are right. The change in group means the valence electrons of the phosphorus make a more stable element and requiring more energy to eject. In sulfur the energies are lowered by electron repulsion. And that the sulfur electrons are at a higher energy. I had looked up the ionization energies in a chart, but my explanation was from a general rule I learned long ago sorry.
PeacefulChaos
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5/3/2014 11:35:01 PM
Posted: 2 years ago
At 5/3/2014 10:47:17 PM, Defro wrote:
This is a great idea. I could make a thread on AP Biology and AP English.

I could help a little bit with AP Biology, as I took that last year.

I'm currently taking AP Language Arts, so I could also contribute to that. (Although, I don't know if you can "study" for English. Just practice multiple choice and writing essays.)
v3nesl
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5/5/2014 8:37:17 AM
Posted: 2 years ago
At 5/2/2014 10:11:43 PM, PeacefulChaos wrote:
Hello, everyone. On Monday I'll be having the AP Chemistry Exam, and so I made this thread to ask some questions and better understand concepts. Hopefully all goes well. If anyone has ever taken this exam, then I'd also greatly appreciate it if you could give me tips or pointers on where specifically to study.

My first question is concerned with ionization energy (specifically, the first one). Would Ga (Gallium) have a lower ionization energy than Ca (Calcium)? Would Indium have a lower ionization energy than Strontium? And so on. Although it goes against the periodic trend of ionization energy, it makes sense that it would require more energy to remove an electron from a fully filled "s" orbital than a "p" orbital. While we're still on the topic of trend inconsistencies, would Phosphorous have a higher ionization energy than Sulfur because Phosphorous has half of its valence electron shell filled?

I'll update this with more questions as time goes on.

Well, maybe you or some other chem whiz lurking here can answer me this: Is it really conceivable that alchohol (as in beer) could ever be made into a powder that you mix with water?

I'm sure you've heard all the stink about powdered alchohol, and I'm just wondering if somebody is pulling a giant prank on the media...
This space for rent.
v3nesl
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5/5/2014 9:45:14 AM
Posted: 2 years ago
At 5/5/2014 8:37:17 AM, v3nesl wrote:
At 5/2/2014 10:11:43 PM, PeacefulChaos wrote:
Hello, everyone. On Monday I'll be having the AP Chemistry Exam, and so I made this thread to ask some questions and better understand concepts. Hopefully all goes well. If anyone has ever taken this exam, then I'd also greatly appreciate it if you could give me tips or pointers on where specifically to study.

My first question is concerned with ionization energy (specifically, the first one). Would Ga (Gallium) have a lower ionization energy than Ca (Calcium)? Would Indium have a lower ionization energy than Strontium? And so on. Although it goes against the periodic trend of ionization energy, it makes sense that it would require more energy to remove an electron from a fully filled "s" orbital than a "p" orbital. While we're still on the topic of trend inconsistencies, would Phosphorous have a higher ionization energy than Sulfur because Phosphorous has half of its valence electron shell filled?

I'll update this with more questions as time goes on.

Well, maybe you or some other chem whiz lurking here can answer me this: Is it really conceivable that alchohol (as in beer) could ever be made into a powder that you mix with water?

I'm sure you've heard all the stink about powdered alchohol, and I'm just wondering if somebody is pulling a giant prank on the media...

So I googled it, and apparently alcohol can be "molecularly encapsulated". So it's still [liquid] alcohol, just in a very small container.
This space for rent.
PeacefulChaos
Posts: 2,612
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5/6/2014 7:49:33 PM
Posted: 2 years ago
At 5/5/2014 9:45:14 AM, v3nesl wrote:
At 5/5/2014 8:37:17 AM, v3nesl wrote:
At 5/2/2014 10:11:43 PM, PeacefulChaos wrote:
Hello, everyone. On Monday I'll be having the AP Chemistry Exam, and so I made this thread to ask some questions and better understand concepts. Hopefully all goes well. If anyone has ever taken this exam, then I'd also greatly appreciate it if you could give me tips or pointers on where specifically to study.

My first question is concerned with ionization energy (specifically, the first one). Would Ga (Gallium) have a lower ionization energy than Ca (Calcium)? Would Indium have a lower ionization energy than Strontium? And so on. Although it goes against the periodic trend of ionization energy, it makes sense that it would require more energy to remove an electron from a fully filled "s" orbital than a "p" orbital. While we're still on the topic of trend inconsistencies, would Phosphorous have a higher ionization energy than Sulfur because Phosphorous has half of its valence electron shell filled?

I'll update this with more questions as time goes on.

Well, maybe you or some other chem whiz lurking here can answer me this: Is it really conceivable that alchohol (as in beer) could ever be made into a powder that you mix with water?

I'm sure you've heard all the stink about powdered alchohol, and I'm just wondering if somebody is pulling a giant prank on the media...

So I googled it, and apparently alcohol can be "molecularly encapsulated". So it's still [liquid] alcohol, just in a very small container.

Not exactly.

It's the same molecules, but it seems to be in a powdered form, so that when it reacts with water it dissolves and you have alcohol.

Of course, I've never heard of this till today, so I'm not too knowledgable on it.