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Measurement of a reaction :)


ibquestions

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Hello all :)

I have been sick lately and thus the ability of my brain to contemplate scientific reactions (such as the one below) has gone down the drain... I just can't figure out how to do this and would greatly appreciate some help if anyone is willing to offer :)

How would I scientifically measure the following?

How does the concentration of HCl (in the following reaction) affect how much hydrogen is produced?

Zn(s) + 2HCl(aq) → ZnCl2(aq) + H2(g)

Thank you to all those who are willing to help :) Being sick sucks :(

Have a nice day :)

Edited by ibquestions
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Is this in a practical sense or just theoretically, because I don't understand why you would need to "scientifically measure" this affect when its pretty simple to work out.

Practically, you could just use a pressure sensor or something similar and measure how much H2 is produced with different concentrations of HCl.

Alternatively...

First you would figure out how many moles of Zn and HCl you have and find which is in excess. If HCl is in excess already, increasing the concentration won't change the amount of H2 is produced. However, if Zn is in excess, the increasing the concentration of HCl will increase the amount of H2 produced until it becomes in excess over Zn.

Basically for every 2 moles of HCl you react, 1 H2 molecule is produced, so increasing HCl concentration will increase the amount of H2 you produce as long as there is still Zn to react with.

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Is this in a practical sense or just theoretically, because I don't understand why you would need to "scientifically measure" this affect when its pretty simple to work out.

Practically, you could just use a pressure sensor or something similar and measure how much H2 is produced with different concentrations of HCl.

Alternatively...

First you would figure out how many moles of Zn and HCl you have and find which is in excess. If HCl is in excess already, increasing the concentration won't change the amount of H2 is produced. However, if Zn is in excess, the increasing the concentration of HCl will increase the amount of H2 produced until it becomes in excess over Zn.

Basically for every 2 moles of HCl you react, 1 H2 molecule is produced, so increasing HCl concentration will increase the amount of H2 you produce as long as there is still Zn to react with.

Haha yes I understand that, I should have rephrased the question, sorry :) (i was tired :P)

I meant how would I measure this reaction in a lab, what equipment could I use to measure the amount of gas produced, etc (My school doesn't have a lot of top en equipment... so it would all need to be fairly basic materials. I just can't seem to figure out how to carry this out in a lab. :(

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Haha yes I understand that, I should have rephrased the question, sorry :) (i was tired :P)

I meant how would I measure this reaction in a lab, what equipment could I use to measure the amount of gas produced, etc (My school doesn't have a lot of top en equipment... so it would all need to be fairly basic materials. I just can't seem to figure out how to carry this out in a lab. :(

Hi,

There are several methods to do this. The first is to connect the flask your reaction is taking place in with a gas syringe.

gas-syringe.gif

A second option, my favourite, would be the downward displacment of water.

post-21678-0-12090100-1299160454_thumb.j

Both are very doable. Hope this helps!

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Haha yes I understand that, I should have rephrased the question, sorry :) (i was tired :P)

I meant how would I measure this reaction in a lab, what equipment could I use to measure the amount of gas produced, etc (My school doesn't have a lot of top en equipment... so it would all need to be fairly basic materials. I just can't seem to figure out how to carry this out in a lab. :(

Hi,

There are several methods to do this. The first is to connect the flask your reaction is taking place in with a gas syringe.

gas-syringe.gif

A second option, my favourite, would be the downward displacment of water.

post-21678-0-12090100-1299160454_thumb.j

Both are very doable. Hope this helps!

Thank you so much :D this helped a lot!! :)

(is there anyway I can look at that attachment without downloading it... it won't let me for some reason :( )

Edited by ibquestions
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  • 2 weeks later...

To my understanding the "downward displacement of water" would be the same thing as shown in the diagram except the flask has tubing that is connected to an inverted graduated cylinder full of water in a bin also full of water. When the reaction in the flask occurs, the Hydrogen gas produced will displace the water in the graduated cylinder. Hope this helps! (It's hard to explain without a diagram)

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