This is the data I collected during a mock calorimeter experiment: Table 11.1: T

Question

This is the data I collected during a mock calorimeter experiment:

Table 11.1: Time-Temperature data for acid-base and redox reaction.

Part A----------------------------------------------Run 1---------Run 2
volume of HCl solution (mL)---------------------50-------------50
molarity of HCl solution (M)---------------------2.005----------2.005
volume of NaOH solution (mL)------------------53.35----------53.25
molarity of NaOH solution (mL)-----------------1.995----------1.995
initial temperature of HCl solution (*C)--------20.8-----------21.2
initial temperature of NaOH solution (*C)------21.2-----------21.0
highest temp. of solution (*C) when mixed----34.1-----------34.5

Part B-----------------------------------------------Run 1----------Run 2
mass of weighing paper (g)----------------------.5179----------.5035
mass Mg (g)-----------------------------------------.4050----------.4040
volume of HCl solution (mL)--------------------50.0------------50.0
molarity of HCl solution (mL)-------------------2.005----------2.005
volume of water added to HCl solution (mL)--50.0-----------50.0
initial temperature of HCl solution (*C)--------22.0------------22.0
highest temp. of solution (*C) when mixed----40.9------------39.7

Following the experiment, I needed to calculate and fill in this chart:

Table 11.2: Heat capacity and enthalpy change.

Part A----------------------------------------------Run 1---------Run 2
Average initial temp. of HCl and -------------21.0-----------21.1
NaOH solution (*C)
Max. temp. of HCl-NaOH solution (*C)-----34.1-----------34.5
Max. temp change for reaction (*C)----------13.1------------13.4
Total volume of HCl plus NaOH --------------103.25--------103.25
solution (mL)
Mass final NaCl solution (g)-------------------*.107----------*.107
Heat produced from HCl-NaOH --------------*5.51---------*5.63
reaction (J)
Moles of H2O formed (mol)--------------------____-----------_____
Heat expected from moles of H2O -----------_____----------_____
formed (J)
Heat absorbed by calorimeter (J)--------------_____----------_____
Heat capacity of calorimeter (J/*C)-----------_____----------_____
Avg. heat capacity of calorimeter (J/*C)-----_____----------_____

Part B----------------------------------------------Run 1---------Run 2
Max. temp. of solution (*C)--------------------40.2-----------39.7
Max temp. change for reaction (*C)----------18.2-----------17.7
Total mass of final solution (g)----------------____-----------_____
Heat required to raise solution to-------------_____----------_____
maximum temp. (J)
Heat required to raise colorimeter -----------_____-----------_____
to max. temp. (J)
Total heat evolved per mole of Mg (J/mol)-_____-----------_____
Enthalpy change for reaction (J)--------------_____-----------_____
Avg. enthalpy change for reaction (J)-------______-----------_____

Basically, my problem is that I do not know whether I am doing some of the calculations correctly. And the biggest problem is that I need the previous calculations to do the ones that follow. I know the basic formulas: q = MCDT, moles = g/gfm, M = moles/L, however I am having a lot of difficulty.

For the ones that I stared above I did my calculations as follows:

Mass of final NaCl solution:
D = m/V and I was given that I should assume that the density of a 1M NaCl solution is 1.04 g/mL.

1.04 g/mL = m/.10325L = .10738 g NaCl

- I do not think this is correct because the density of NaCl is in mL, however, when I keep my volume at 103.25 mL I get 107.38 g NaCl and I do not see how that is possible due to the conservation of mass.

Going from this, for the heat produced from the reaction of HCl-NaOH I got:
Assuming that the heat capacity of a 1M NaCl solution is 3.93 J/g*C
q = MDT
q = (.107 g NaCl)(3.93 J/g*C)(13.4*C) = 5.63 J

** for the total theoretical heat expected I am to assume that 57,320 J are produced per mole of water formed

For Part B calculations:
Total mass of final solution (density of 2M Hcl is 1.03 g/mL) and the mass of water (1.00 g/mL):

Mass of initial solution 1.03 g/mL = mass/ 50.0mL = 51.5 g----- I believe I did this right but I am not 100 percent sure and I am apprehensive to proceed wit the following questions regarding Part B.

** assume heat capacity of final MgCl2 solution is 3.97 J/g*C

I apologize for this being so long but I had missed school and this lab because one of my family members ended up in the hospital. I had to make up the lab by myself and my teacher is out after having surgery for carpal tunnel.

I do not even really need the answers, more I just need the equations on how to get the answers for the several blanks I have in my Table 11.2 chart. With the information, I know I

Explanation / Answer

Part A

firstly

Average initial temperature is determined by taking volumes into acount because had their volume been equal you might have taken simple average

here 50 (20.8) + 53.35(21.2)=Tav(50+53.35)=103.35Tav

Tav=2171.02/103.35=21.0065oC although its almost equal to 21.0

2ndly

Moles of H2O formed is determined as : we know that 1mole of HCl reacts with 1mole of NaOH

HCl + NaOH ==>NaCl + H2O

therefore multiply the molarity with the volume of HCl or similarly for NaOH to determine their moles.

moles of HCl=molarity*volume=2.005moles/L*0.050L=0.10025moles of HCl

moles of NaOH=1.995moles/L*0.05335L=0.1064moles of NaOH

so moles of H2O formed would be equal to moles of HCl=0.10025=0.1moles

3rdly

mass of solution is determined from =density*total volume of solution=1.04g/mL*103.35mL=107.484g solution

now for mass of NaCl produced is determined as

since we know that moles of H2O produced= moles of NaCl produce=0.1moles

mass of NaOH=moles of NaCl*molar mass=0.1moles*58.5g/mole=5.85g NaOH

4thly

Heat produced=q=mcDeltaT=(5.85g*3.93J/g-oC*13.4oC)=308.073J=0.3081kJ

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