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casper29
Mar 16, 2009, 02:22 PM
So for class we have to create a major lab for chemistry and the chemicals we are able to use are hydrochloric acid, zinc, copper sulfate and sodium hydroxide. My partner and I chose to create an experiment using zinc and HCl (hydrochloric acid) where we are observing the hydrogen released after the reaction.
OK. So first we will add zinc to the HCl and observe the hydrogen released yet how in the world would I measure that?? Then we will heat the HCl to oxidize it and add zinc again, the same amount, and observe if the amount of hydrogen released is the same. Again, how would that be measured?
And some people are doing percent yield and using stoichiometry but I'm terrible at science so I have no idea what I am measuring for in the hydrogen, be it moles, or grams or whatever... so what should I measure for and how do I apply it to the lab??
Anyhelp would be greatly appreciated.
Thanks! :confused:

Capuchin
Mar 16, 2009, 02:45 PM
An easy way to measure the amount of hydrogen produced would be to capture your released gas in a syringe. This would give you a volume of h2. Using this and a measurement of the room temperature and pressure would enable you to use your knowledge of how gasses behave (PV=nRT) to calculate the number of moles.

It's important that you use a syringe, as this will enable the pressure inside your equipment to equal the pressure outside. Something like a balloon would increase the interior pressure.

Perito
Mar 16, 2009, 03:12 PM
Often, in science class, a large graduated cylinder is filled with water and placed upside down in a pan of water. A tube is routed from the reaction flask through the pan of water and into the open mouth of the graduated cylinder. As gas is evolved, it can be measured directly from the markings on the graduated cylinder.