Volume of liquid question (1 Viewer)

[Cleavage]

My chem class discussed the following question in class today. My teacher is quite ignorant, particularly regarding calculation questions, and refuses to explain the answer (because she can't do it);

1. Write a balanced equation for complete combustion of ethanol with oxygen producing carbon dioxide and water.

2. If 98L of CO2 is formed at 25 degrees, and 100kpa, calculate the mass of ethanol used in the reaction.

3. Use the data from part 2 to calculate the volume of the liquid water formed when the products are condensed at 25 degrees and 100kpa.


(Question is from conquering chem) Can someone create a worked solution?

 

[Cleavage]

I forgot to add, I'm really only looking for a worked solution to part 3

 

[anomalousdecay]

From 2 and using the data sheet:



Find the moles of Water produced with accordance to the moles of Carbon Dioxide gas produced, using the balanced equation in 1.



Then calculate the volume produced using the data sheet and the moles of Water produced.





The answer is exact lol.

EDIT: Is it showing for you? From my end LaTex is not working.

But the answer in short is:

Volume of Water produced = 147 L

 

[Cleavage]

Yeah 147L is the textbook answer. I can't see your LaTex either.

I tried to get volume of water by working out moles of water in the equation (as a ratio with the carbon dioxide), then calculate the mass of water and as such volume of water.

With this method, I got around 107L of water. Is the method above valid?

 

[anomalousdecay]

Can you read LaTex though? The answer is in full there.

Maybe your equation is wrong? I got 3 moles of Water for 2 moles of Carbon Dioxide. You don't need the mass of water though.

You just get the moles of water and use the data sheet info and that's it.

 

[yasminee96]

Here's a screenshot of anoms post in case you still can't see it:

 

[Cleavage]

Here's a screenshot of anoms post in case you still can't see it:

View attachment 29957

Cheers

I had the right equation, yeah hmmm whatever I suppose, the method you used is far simpler and more logical.

 

[mysterymarkplz]

I don't understand, how can you use the volume of gas at room temperature for V(H2O) when the question says the products were cooled down to 25*? Doesn't that imply H2O is a liquid, hence you can't use the 24.79L = 1 mole to calculate H2O's volume?

 

[anomalousdecay]

After reporting the LaTex issue (it had been ongoing for a month or so) LaTex should be working absolutely fine now!

I don't understand, how can you use the volume of gas at room temperature for V(H2O) when the question says the products were cooled down to 25*? Doesn't that imply H2O is a liquid, hence you can't use the 24.79L = 1 mole to calculate H2O's volume?

It said that it condensed into liquid. I'm guessing its in gas form originally at 25*C but then it it rapidly changed into liquid due to pressure.

Good question though (not sure though as its been 4 months and I'm a bit rusty now). This is where I need a textbook lol.

 

[mysterymarkplz]

regardless the volume of a gas is not retained despite being condensed to liquid, or am i mistaken?

 

[anomalousdecay]

regardless the volume of a gas is not retained despite being condensed to liquid, or am i mistaken?

Yes but you missed the point of my previous post:

It said that it condensed into liquid. I'm guessing its in gas form originally at 25*C but then it it rapidly changed into liquid due to pressure.

So what I was saying is that its asking how much gas was produced before it became a liquid (at least it should be saying that to make some sort of sense Chemistry-wise).

 

[someth1ng]

The volume of liquid water should be significantly lower than 147 L - it should be ~106 mL.

anomalousdecay, I don't know why you're trying to argue that it's asking for the gas volume - it's clearly asking for the volume of "liquid water".

 

[yasminee96]

Someone explain the question to me. It's saying the products are condensed at SLC right ...
So then it's pretty much asking to use the moles of water found using the previous question and then using the SLC formula thingy to find it's volume ...

So then we would assume that it wasn't initially a liquid correct?

So what's everyone fussing about?

#lost


Sent from my iPhone using Tapatalk

 

[QZP]

The volume of liquid water should be significantly lower than 147 L - it should be ~106 mL.

anomalousdecay, I don't know why you're trying to argue that it's asking for the gas volume - it's clearly asking for the volume of "liquid water".

Yeah I got 106.8 mL.

 

[iStudent]

The volume of liquid water should be significantly lower than 147 L - it should be ~106 mL.

anomalousdecay, I don't know why you're trying to argue that it's asking for the gas volume - it's clearly asking for the volume of "liquid water".

Yea 106mL is what I got as well. If you think about it, 147L of liquid water doesn't really make sense haha. (that's like 147 Litre buckets!)
As a tip, this question involved finding the concentration of water in water

 

[QZP]

Yea 106mL is what I got as well. If you think about it, 147L of liquid water doesn't really make sense haha. (that's like 147 Litre buckets!)
As a tip, this question involved finding the concentration of water in water

wtf is "concentration of water in water"

 

[iStudent]

wtf is "concentration of water in water"

Never mind, realised I took the long way of solving it. I'll post my stupid method later so everyone can laugh at me, lol. (still got the correct answer though )

 

[anomalousdecay]

The volume of liquid water should be significantly lower than 147 L - it should be ~106 mL.

anomalousdecay, I don't know why you're trying to argue that it's asking for the gas volume - it's clearly asking for the volume of "liquid water".

I was saying what the textbook was assuming as I got what the textbook answer is (though come to think of it, the textbook question seems wrong for that answer).

I am not saying that 106.8mL is the incorrect answer.

I am saying that the question's answer assumed that and hence got the 147L.

So obviously the question is worded wrong.