[abacha7]

I have some lab questions but not sure how to answer.Ill explain the lab.Please see if you can answer any of the following.

So yesterday I did a chem lab,and we had two seperate labs.The first was burning Magnesium strips and getting the burned remains of it,and weighing it. The second lab was quite confusing.We got a long test tube and filled 1/3 of it with HCL(hydrochloric acid)the rest of it (2/3)we filled with water.We than got a piece of magnesium and wrapped it up with copper.than twiist the remainding copper to attach with the rubber stopper so that wen the stopper was placed on the long test tube,the copper and magnesium was in.We than submerged it underwater and I put my finger to block the hole in the stopper.What happend was the hcl burned through the mg and wat was remaining was copper and hcl floating on top of water.After that we got a big graduated cylinder and submerged the long test tube once again upside down in it.We put the water + hcl in the long testube to level with the water in the graduated cylinder.Some thing occured in the test tube(not sure).

Please and Thanks


Here are the lab questions:

1. account for the yield that was not 100%
2. what was a likely unintended product of the first reaction?
3. what is the purity of HCL and how might this impact results?
4. explain why it was neccessary to equilibrate pressure in part 2?
5. calculate the mass of O2 consumed in part 1 and moles of HCL consumed in part 2. (HCL= 6.0 mol/L) *Actually consumed*

[abacha7]

Sorry,here is what I got so far...

1.I got a % yield of 63.I am not sure how to incorporate my results in the answer.I am not sure what it is asking.

2.The first reaction was Mg+O2 so the product is 2Mg0.The unlikely product I am not sure.I cant see anyother product being made.

3.I am not sure what it means by purity of HCL.The HCl is 6.0 mol/l,also It looked like there was no impurites so Im guessing the purity of it was quite high.But I am not sure that is the answer my teacher is looking for.

4.I am not sure why they wanan equillibrate pressure.The only thing I can think of is that with a equal pressure in and outside the test tube,than the reaction can perform.

5. The chemical equation is 2Mg+ O2 -> 2MgO ---so im guessing that for every 2 Mg you need 1 O2.So since I got 2 Mg strips,I would divide the mass of both and use taht number for O2 that was needed.

[Borek]

http://en.wikipedia.org/wiki/Magnesium_nitride

I am not sure why they wanan equillibrate pressure.

Have you measured the volume of gas?