CHEM 1211 Lab Manl-Revised 0/2017 Calculations (Show all work for trial one. Use
ID: 544965 • Letter: C
Question
CHEM 1211 Lab Manl-Revised 0/2017 Calculations (Show all work for trial one. Use the back if you need more space.)( 12 pts.) 00159 293.2 zota73.2s a9 3.2 x:oo .. :/2010 The calculation for R hinges on the assumption that Mg the calculations that demonstrate this for Trial 1. Also is the limiting reagent. how your calculations prove the limiting reagent. (6 pts): Prior to placing the eudiometer into the Equalization Chamber, is the pressure of the gas inside the tube greater than or less than the pressure outside the tube? Comparing the volume of the gas before and after placing the eudiometer into the Equalization Chamber should help with the explanation. Explain your logic. (4 pts): What experimental measurement most affected the accuracy of the experimental value of R? Explain. (HINT: Consider the significant figures in your data.) (3 pts.) What experimental changes might improve the accuracy of the determined R value? pts.) (3 64Explanation / Answer
Mass of Mg = 0.046 gm
Mol of Mg = 0.046 gm / 24.3056 gm/mol = 1.8925*10-3 mol
According to the reaction stoichiometry,
1 mol of Mg reacts with 2 mol of HCl so mol of HCl will be 2 times that of Mg
i.e) 2*1.8925*10-3 = 3.785*10-3 mol
This shows that Mg is indeed the limiting reactant.
The pressure outside the tube is greater than the inside atmospheric pressure.
This you will know by comparing the volumes as it was asked in the question, the liquid
level is higher than level when placed inside the chamber.
Pressure measurement most of the times will be inaccurate, to get close values of R
sometimes corrected pressures are used.
The following experimental changes might improve the accuracy in the determined R value
(i) Adding exact volumeof HCl into eudiometer tube (ii) Recording the temperature after
perfect equilibrium is attained (iii) weighing the Mg i.e) even considering at least 4 significant figures