CHM110H5 Lecture Notes - Lecture 1: Burette, Atomic Mass, Kepler-86

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plumsardine237

14 Apr 2016

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Part a: determination of the atomic mass of a metallic element. A metallic element"s atomic mass can be determined by using several methods. One of the methods that is used in this experiment was based on the following reaction of the metal with aqueous acid: This equation can be used to calculate the number of moles of h2 (g) produced by the metal whose weight is known. The atomic mass can then be determined by using the number of moles. Then the results that are measured can be analysed to determine the molecular mass of the metal on the basis of stoichiometric equation. To determine the unknown metal used in the reaction. Table 1: values of the data collected during the experiment. Calculations: the following equation can be used to express the hydrostatic pressure ( h) in torr: Soln hsoln = hg hhg where soln = 1. 00g/ml, hg =13. 6g/ml, hsoln = 30. 8cm.

Related Questions

given data:moles of H2=0.001mole , given weight of the unknown metal(M)=0.0757 ggiven equation:M(s)+nH30^+1........>M^(+n)+ (n/2) H2 + nH2Ofrom the stoichiometry of the reaction and the number of moles of H2 given,calculate the number of moles of metal in the sample.Assume that n in the balanced equation for the reaction is either 2 or 3.From the weight of the sample,then determine the two possible atomic masses of metals.Consult the periodic table to see which more nearly corresponds to a known metallic element.

Do Question Number 6

Change in enthalpy equation help

I am working on calculations for a change in enthalpy/Hess's law experiment, we used calorimeters and reacted 100mL of HCl (in excess) with .152g Mg. Our initial temperature was 20.0C and final temperature was 26.5C. We determined that Ccal for the calorimeter was 56 J/C. How do I determine delta H, the change in enthalpy per mole?

I am currently using the formula

delta H= (mc(Tfinal-Tinitial)+Ccal(Tfinal-Tinitial))/n

Where m = mass

c= specific heat, in this case using 4.184J/g*C (as directed by professor)

and n = number of moles

Does my equation look correct?

I calculated n using the mass of the Mg sample and dividing it by the molar mass of Mg

What do I use as the mass for the experiment?

Do I use the mass of the Mg sample?

The mass of the reactants spent in the reaction? This would be taking the number of moles of Mg present and multiplying it by 2 (since two moles of HCl react with 1 mole of Mg) and the multiplying it by the molar mass of Mg.

Or is it the total mass of the stuff in the calorimeter, so the mass of the Mg sample and the mass of the 100mL of 1.0M HCl?

Help would be appreciated, I've been working on this for 20 hours, most of it trying to figure out what to do, I did try talking to our lab professor but he didn't want to help me.

CHM110H5 Lecture Notes - Lecture 1: Burette, Atomic Mass, Kepler-86

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