3.3: Experimental Procedures
- Page ID
- 374482
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\(\newcommand{\avec}{\mathbf a}\) \(\newcommand{\bvec}{\mathbf b}\) \(\newcommand{\cvec}{\mathbf c}\) \(\newcommand{\dvec}{\mathbf d}\) \(\newcommand{\dtil}{\widetilde{\mathbf d}}\) \(\newcommand{\evec}{\mathbf e}\) \(\newcommand{\fvec}{\mathbf f}\) \(\newcommand{\nvec}{\mathbf n}\) \(\newcommand{\pvec}{\mathbf p}\) \(\newcommand{\qvec}{\mathbf q}\) \(\newcommand{\svec}{\mathbf s}\) \(\newcommand{\tvec}{\mathbf t}\) \(\newcommand{\uvec}{\mathbf u}\) \(\newcommand{\vvec}{\mathbf v}\) \(\newcommand{\wvec}{\mathbf w}\) \(\newcommand{\xvec}{\mathbf x}\) \(\newcommand{\yvec}{\mathbf y}\) \(\newcommand{\zvec}{\mathbf z}\) \(\newcommand{\rvec}{\mathbf r}\) \(\newcommand{\mvec}{\mathbf m}\) \(\newcommand{\zerovec}{\mathbf 0}\) \(\newcommand{\onevec}{\mathbf 1}\) \(\newcommand{\real}{\mathbb R}\) \(\newcommand{\twovec}[2]{\left[\begin{array}{r}#1 \\ #2 \end{array}\right]}\) \(\newcommand{\ctwovec}[2]{\left[\begin{array}{c}#1 \\ #2 \end{array}\right]}\) \(\newcommand{\threevec}[3]{\left[\begin{array}{r}#1 \\ #2 \\ #3 \end{array}\right]}\) \(\newcommand{\cthreevec}[3]{\left[\begin{array}{c}#1 \\ #2 \\ #3 \end{array}\right]}\) \(\newcommand{\fourvec}[4]{\left[\begin{array}{r}#1 \\ #2 \\ #3 \\ #4 \end{array}\right]}\) \(\newcommand{\cfourvec}[4]{\left[\begin{array}{c}#1 \\ #2 \\ #3 \\ #4 \end{array}\right]}\) \(\newcommand{\fivevec}[5]{\left[\begin{array}{r}#1 \\ #2 \\ #3 \\ #4 \\ #5 \\ \end{array}\right]}\) \(\newcommand{\cfivevec}[5]{\left[\begin{array}{c}#1 \\ #2 \\ #3 \\ #4 \\ #5 \\ \end{array}\right]}\) \(\newcommand{\mattwo}[4]{\left[\begin{array}{rr}#1 \amp #2 \\ #3 \amp #4 \\ \end{array}\right]}\) \(\newcommand{\laspan}[1]{\text{Span}\{#1\}}\) \(\newcommand{\bcal}{\cal B}\) \(\newcommand{\ccal}{\cal C}\) \(\newcommand{\scal}{\cal S}\) \(\newcommand{\wcal}{\cal W}\) \(\newcommand{\ecal}{\cal E}\) \(\newcommand{\coords}[2]{\left\{#1\right\}_{#2}}\) \(\newcommand{\gray}[1]{\color{gray}{#1}}\) \(\newcommand{\lgray}[1]{\color{lightgray}{#1}}\) \(\newcommand{\rank}{\operatorname{rank}}\) \(\newcommand{\row}{\text{Row}}\) \(\newcommand{\col}{\text{Col}}\) \(\renewcommand{\row}{\text{Row}}\) \(\newcommand{\nul}{\text{Nul}}\) \(\newcommand{\var}{\text{Var}}\) \(\newcommand{\corr}{\text{corr}}\) \(\newcommand{\len}[1]{\left|#1\right|}\) \(\newcommand{\bbar}{\overline{\bvec}}\) \(\newcommand{\bhat}{\widehat{\bvec}}\) \(\newcommand{\bperp}{\bvec^\perp}\) \(\newcommand{\xhat}{\widehat{\xvec}}\) \(\newcommand{\vhat}{\widehat{\vvec}}\) \(\newcommand{\uhat}{\widehat{\uvec}}\) \(\newcommand{\what}{\widehat{\wvec}}\) \(\newcommand{\Sighat}{\widehat{\Sigma}}\) \(\newcommand{\lt}{<}\) \(\newcommand{\gt}{>}\) \(\newcommand{\amp}{&}\) \(\definecolor{fillinmathshade}{gray}{0.9}\)Experimental Procedures
Part 1: Preparing solutions
Solution 1
- Weigh an empty 25 mL volumetric flask and record the mass in your data sheet to the precision of your instrument
- Weigh approx 0.5 g sodium chloride and add to the 25 mL volumetric flask.
- Weigh the flask with the solid solute and record the mass in your data sheet to the precision of your instrument
- Fill the flask a bit over half way to mark with deionized water and swirl to dissolve all the solute. Continue filling to mark, using an eye dropper to add the last few drops. Be sure all the solute is dissolved
- Weigh the volumetric flask with aqueous salt solution and record the mass in your data sheet to the precision of your instrument
- Pour the solution from the volumetric flask into a 100 mL beaker labeled #1 and set aside. You will use it in part 2.
- Clean the volumetric flask with DI water. You do not need to dry it.
Solution 2
- Repeat steps 1-5 for solution 1 but use approximately 3 g of NaCl.
- Pour solution into 100 mL beaker labeled #2 and set aside. You will use it in part 2.
Part 2: Freezing point determination
- Obtain a Vernier LabQuest, hook up the temperature probe and set it to "meter" with the scale reading in oC. Instructions for running the LabQuest are in the Instrumentation section of your lab manual (sections 0.4.1 & 0.4.2).
- Fill a 150mL beaker about 1/3 full with ice, pour water over it, insert temperature probe into ice water and once the temperature stabilizes record the temperature of the pure water and ice mixture.
- Place about 10 mL of solution #1 into the 8 in test tube and insert digital temperature probe. Keep test tube in an empty Erlenmeyer flask when not using.
- Add a small amount of dry ice to the bottom of calorimeter and insert 8 in test tube with solution 1 and temperature probe into calorimeter.
- Observe the temperature decrease until it stabilizes, which will occur when the salt solution begins to form ice, remove test tube from calorimeter and place in the ice water beaker, stirring with temperature probe (This slows down the warming so you have more time to observe). Be sure the ice floats to the top.
- Record the temperature the moment the last bit of ice melts. This will be considered the freezing point of the solution of the salt concentration you made.
- Using a second 8 in test tube repeat steps 3-6 for solution #2.
- Have instructor check data
- Repeat trial for all solutions if instructed(you can use the same test tubes and solution)
- Place waste in waste container and clean up your work station.