Question

Okay so I'm really confused on finding percent yield I keep doing these problems and they aren't adding up can someone please check my work?

Answer 1

1. Write the balanced equation for the reaction conducted in this lab, including appropriate phase symbols.
Mg(s) + 2HCl(aq) --> MgCl2(aq) + H2(g)
2. Determine the partial pressure of the hydrogen gas collected in the gas collection tube.
change 22.4torr to atm
22.4torr x [1atm / 760torr] = 0.0295atm.
Ptotal = Pwater + Phydrogen
Phydrogen = Ptotal - Pwater = 1.10atm - 0.0295 = 1.0705atm.
3. Calculate the moles of hydrogen gas collected.
n = PV / RT = 1.0705atm x 0.0322L / (0.0821Latm/moleK x 297K) = 0.00141moles H2
4. If magnesium was the limiting reactant in this lab, calculate the theoretical yield of the gaseous product. Show all steps of your calculation.
0.034gMg x [1moleMg/24.3gMg] x [1moleH2 / 1moleMg] = 0.00140moles
0.00140 x 22.4L = .03136L
5. Determine the percent yield of this reaction, showing all steps of your calculation.

Answer 2

Percentage yield is just
\[\frac{actual~yield}{theoretical~yield} \times 100\%\]

Answer 3

So it would be 0.44 %
I'm just not sure if the rest of the work is correct

Answer 4

Did they gave you the actual yield?

Answer 5

What's the original question?

Answer 6

No this is all I have plus this
Mass of Magnesium Strip (grams) 0.034
Volume of gas collected (mL) 32.2
Barometric pressure (atm) 1.1
Room temperature (C ) 24
Vapor pressure of the water (torr) 22.4

Answer 7

Hmm, the volume of gas collected should be the actual yield

Answer 8

So then it's the moles of gas that's the actual yield?

Answer 9

yeah but it seems that you're getting almost 100% yield, that's weird :\

Answer 10

But if the gas are almost ideal, and the reactant is limiting reagent completely reacts and that there's no gas escaped/ any changes then you should get almost the theoretical yield

Answer 11

@chmvijay

Answer 12

I get 0.0998%, i converted mL to meters cubed and used R as 8.31

Answer 13

I got 100% ( exact : 100.00003 ... %)

Answer 14

My last equation set up was :

% Yield = 2.82396 / 2.823 * 100%

Answer 15

Yes that's what I'm getting as well, but something doesn't feel right, @chmvijay

Answer 16

Where did you get 24.3gmL in the fourth problem