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The enthalpy of a reaction might be difficult to obtain directly by experiment but can be determined by measuring (or looking up in tables) the enthalpy changes of reactions which contain the reactants and products in a process governed by Hess's Law of Heat Summation. In Part II of this experiment you are asked to find the enthalpy of hydration of CaCl 2 ( s ) size 12{ ital "CaCl" rSub { size 8{2} } \( s \) } {} the "target reaction" in this manner.

Target reaction:  CaCl 2 + 6H 2 O = CaCl 2 6H 2 O size 12{ ital "CaCl" rSub { size 8{2} } +6H rSub { size 8{2} } O= ital "CaCl" rSub { size 8{2} } cdot 6H rSub { size 8{2} } O} {}

It cannot be measured directly because of the slow kinetics of the reaction in the solid state. However, the heats of dissolution of CaCl 2 size 12{ ital "CaCl" rSub { size 8{2} } } {} and CaCl 2 6H 2 O size 12{ ital "CaCl" rSub { size 8{2} } cdot 6H rSub { size 8{2} } O} {} can be determined and, using Hess's Law, the enthalpy of hydration can be calculated.

Theoretical value of the enthalpy of hydration of CaCl 2 size 12{ ital "CaCl" rSub { size 8{2} } } {} anhydrous is -81.33kJ/mol. Theoretical value of the enthalpy of hydration of CaCl 2 6H 2 O size 12{ ital "CaCl" rSub { size 8{2} } cdot 6H rSub { size 8{2} } O} {} is 15.79 kJ/mol.

Experimental procedure

Materials required

  • two Styrofoam cups (serve as the calorimeter)
  • styrofoam cover (top to the calorimeter)
  • conventional or digital thermometer
  • stirring motor and stir bar
  • two large Ziploc bag
  • two plastic spoons

Setup of the microlab thermistor

  • Open the MicroLab Program by clicking on the Shortcut to MicroLab.exe tab on the desktop.
  • On the“Choose an Experiment Type”Tab, enter a name for the experiment, and then double click on the MicroLab Experiment icon
  • Click“Add Sensor”, Choose sensor = Temperature (thermistor)
  • Choose an input, click on the red box that corresponds to the port that your thermistor is connected to.
  • Label = Thermistor, sensor units = ° C size 12{°C} {} , click next
  • Click“Perform New Calibration”
  • Click“Add Calibration Point”place the thermistor and thermometer in an ice water bath. Wait until the temperature is constant and then read the temperature on the thermometer (to the nearest 0.1 ° C size 12{°C} {} ) and enter it into the“Actual Value”box in MicroLab and hit“ok”.
  • Again, Click“Add Calibration Point”place the thermistor and thermometer in warm water bath. Wait until the temperature is constant and then read the temperature on the thermometer (to the nearest 0.1 ° C size 12{°C} {} ) and enter it into the“Actual Value”box in MicroLab and hit“ok”.
  • Under Curve Fit Choices , click on“First order (linear)”and then“Accept and Save this Calibration”, when prompted to enter units, set as deg C. Save as your name-experiment-date.
  • Click“Add Sensor”, Choose sensor = Time
  • Choose an input, click on the red box that corresponds any of the Timers.
  • Label = Time 1, click next, click Finish.
  • Left click on thermistor and drag to the Y-axis over“data source two”, also click and drag to column B on the spreadsheet and also click and drag to the digital display window.
  • Left click on Time and drag to the X-axis over“data source one”, also click and drag to column A on the spreadsheet and also click and drag to the digital display window.
  • When you are ready to obtain data, click start. When you are finished collecting data, click stop. To run another trial, click repeat experiment.

Part i. reaction of strong acid with strong base

  • Weigh the calorimeter (styrofoam cups with lid) WITH a stir bar. Accurately measure 50 mL of 1 M HCl into your calorimeter. Turn on the stirring motor to the medium speed. Fit the thermistor though the cardboard lid to a length such that its tip goes deep into the solution but misses the stir bar. Cover the calorimeter.
  • Start the Acquisition program. You should see successive, constant temperature readings of near room temperature. Accurately measure 50 mL of 1 M NaOH and quickly add it to the acid solution in the Styrofoam cups. Cover the calorimeter.
  • Continue monitoring the temperature change until thermal equilibrium is reached (the temperature stops changing or starts decreasing).
  • Stop the Acquisition program. SAVE YOUR FILE. Remove the cardboard lid, reweigh the calorimeter and record the information on your lab report.
  • Repeat the same procedure (Steps 1-4) two more times. Save all your files. Give them different, distinguishable names.

Questions & Answers

where we get a research paper on Nano chemistry....?
Maira Reply
nanopartical of organic/inorganic / physical chemistry , pdf / thesis / review
Ali
what are the products of Nano chemistry?
Maira Reply
There are lots of products of nano chemistry... Like nano coatings.....carbon fiber.. And lots of others..
learn
Even nanotechnology is pretty much all about chemistry... Its the chemistry on quantum or atomic level
learn
Google
da
no nanotechnology is also a part of physics and maths it requires angle formulas and some pressure regarding concepts
Bhagvanji
hey
Giriraj
Preparation and Applications of Nanomaterial for Drug Delivery
Hafiz Reply
revolt
da
Application of nanotechnology in medicine
what is variations in raman spectra for nanomaterials
Jyoti Reply
ya I also want to know the raman spectra
Bhagvanji
I only see partial conversation and what's the question here!
Crow Reply
what about nanotechnology for water purification
RAW Reply
please someone correct me if I'm wrong but I think one can use nanoparticles, specially silver nanoparticles for water treatment.
Damian
yes that's correct
Professor
I think
Professor
Nasa has use it in the 60's, copper as water purification in the moon travel.
Alexandre
nanocopper obvius
Alexandre
what is the stm
Brian Reply
is there industrial application of fullrenes. What is the method to prepare fullrene on large scale.?
Rafiq
industrial application...? mmm I think on the medical side as drug carrier, but you should go deeper on your research, I may be wrong
Damian
How we are making nano material?
LITNING Reply
what is a peer
LITNING Reply
What is meant by 'nano scale'?
LITNING Reply
What is STMs full form?
LITNING
scanning tunneling microscope
Sahil
how nano science is used for hydrophobicity
Santosh
Do u think that Graphene and Fullrene fiber can be used to make Air Plane body structure the lightest and strongest. Rafiq
Rafiq
what is differents between GO and RGO?
Mahi
what is simplest way to understand the applications of nano robots used to detect the cancer affected cell of human body.? How this robot is carried to required site of body cell.? what will be the carrier material and how can be detected that correct delivery of drug is done Rafiq
Rafiq
if virus is killing to make ARTIFICIAL DNA OF GRAPHENE FOR KILLED THE VIRUS .THIS IS OUR ASSUMPTION
Anam
analytical skills graphene is prepared to kill any type viruses .
Anam
Any one who tell me about Preparation and application of Nanomaterial for drug Delivery
Hafiz
what is Nano technology ?
Bob Reply
write examples of Nano molecule?
Bob
The nanotechnology is as new science, to scale nanometric
brayan
nanotechnology is the study, desing, synthesis, manipulation and application of materials and functional systems through control of matter at nanoscale
Damian
Is there any normative that regulates the use of silver nanoparticles?
Damian Reply
what king of growth are you checking .?
Renato
What fields keep nano created devices from performing or assimulating ? Magnetic fields ? Are do they assimilate ?
Stoney Reply
why we need to study biomolecules, molecular biology in nanotechnology?
Adin Reply
?
Kyle
yes I'm doing my masters in nanotechnology, we are being studying all these domains as well..
Adin
why?
Adin
what school?
Kyle
biomolecules are e building blocks of every organics and inorganic materials.
Joe
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Source:  OpenStax, Gen chem lab. OpenStax CNX. Oct 12, 2009 Download for free at http://cnx.org/content/col10452/1.51
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