5.R: Calorimetry/Thermochemistry (Report)
- Page ID
- 306768
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\(\newcommand{\avec}{\mathbf a}\) \(\newcommand{\bvec}{\mathbf b}\) \(\newcommand{\cvec}{\mathbf c}\) \(\newcommand{\dvec}{\mathbf d}\) \(\newcommand{\dtil}{\widetilde{\mathbf d}}\) \(\newcommand{\evec}{\mathbf e}\) \(\newcommand{\fvec}{\mathbf f}\) \(\newcommand{\nvec}{\mathbf n}\) \(\newcommand{\pvec}{\mathbf p}\) \(\newcommand{\qvec}{\mathbf q}\) \(\newcommand{\svec}{\mathbf s}\) \(\newcommand{\tvec}{\mathbf t}\) \(\newcommand{\uvec}{\mathbf u}\) \(\newcommand{\vvec}{\mathbf v}\) \(\newcommand{\wvec}{\mathbf w}\) \(\newcommand{\xvec}{\mathbf x}\) \(\newcommand{\yvec}{\mathbf y}\) \(\newcommand{\zvec}{\mathbf z}\) \(\newcommand{\rvec}{\mathbf r}\) \(\newcommand{\mvec}{\mathbf m}\) \(\newcommand{\zerovec}{\mathbf 0}\) \(\newcommand{\onevec}{\mathbf 1}\) \(\newcommand{\real}{\mathbb R}\) \(\newcommand{\twovec}[2]{\left[\begin{array}{r}#1 \\ #2 \end{array}\right]}\) \(\newcommand{\ctwovec}[2]{\left[\begin{array}{c}#1 \\ #2 \end{array}\right]}\) \(\newcommand{\threevec}[3]{\left[\begin{array}{r}#1 \\ #2 \\ #3 \end{array}\right]}\) \(\newcommand{\cthreevec}[3]{\left[\begin{array}{c}#1 \\ #2 \\ #3 \end{array}\right]}\) \(\newcommand{\fourvec}[4]{\left[\begin{array}{r}#1 \\ #2 \\ #3 \\ #4 \end{array}\right]}\) \(\newcommand{\cfourvec}[4]{\left[\begin{array}{c}#1 \\ #2 \\ #3 \\ #4 \end{array}\right]}\) \(\newcommand{\fivevec}[5]{\left[\begin{array}{r}#1 \\ #2 \\ #3 \\ #4 \\ #5 \\ \end{array}\right]}\) \(\newcommand{\cfivevec}[5]{\left[\begin{array}{c}#1 \\ #2 \\ #3 \\ #4 \\ #5 \\ \end{array}\right]}\) \(\newcommand{\mattwo}[4]{\left[\begin{array}{rr}#1 \amp #2 \\ #3 \amp #4 \\ \end{array}\right]}\) \(\newcommand{\laspan}[1]{\text{Span}\{#1\}}\) \(\newcommand{\bcal}{\cal B}\) \(\newcommand{\ccal}{\cal C}\) \(\newcommand{\scal}{\cal S}\) \(\newcommand{\wcal}{\cal W}\) \(\newcommand{\ecal}{\cal E}\) \(\newcommand{\coords}[2]{\left\{#1\right\}_{#2}}\) \(\newcommand{\gray}[1]{\color{gray}{#1}}\) \(\newcommand{\lgray}[1]{\color{lightgray}{#1}}\) \(\newcommand{\rank}{\operatorname{rank}}\) \(\newcommand{\row}{\text{Row}}\) \(\newcommand{\col}{\text{Col}}\) \(\renewcommand{\row}{\text{Row}}\) \(\newcommand{\nul}{\text{Nul}}\) \(\newcommand{\var}{\text{Var}}\) \(\newcommand{\corr}{\text{corr}}\) \(\newcommand{\len}[1]{\left|#1\right|}\) \(\newcommand{\bbar}{\overline{\bvec}}\) \(\newcommand{\bhat}{\widehat{\bvec}}\) \(\newcommand{\bperp}{\bvec^\perp}\) \(\newcommand{\xhat}{\widehat{\xvec}}\) \(\newcommand{\vhat}{\widehat{\vvec}}\) \(\newcommand{\uhat}{\widehat{\uvec}}\) \(\newcommand{\what}{\widehat{\wvec}}\) \(\newcommand{\Sighat}{\widehat{\Sigma}}\) \(\newcommand{\lt}{<}\) \(\newcommand{\gt}{>}\) \(\newcommand{\amp}{&}\) \(\definecolor{fillinmathshade}{gray}{0.9}\)Part A: Exothermic and Endothermic Dissolution of Salts
| NaCl | CaCl2 | KCl | |
|---|---|---|---|
| Equation for dissolution of salt | |||
| Mass of test tube | |||
| Mass of test tube and water | |||
| Mass of water | |||
| Initial temperature of water | |||
| Mass of test tube | |||
| Mass of test tube and salt | |||
| Mass of the salt | |||
| Final temperature | |||
| Is this exothermic or endothermic dissolution? | |||
| Calculate q for the dissolution of the salt | |||
| Calculate the J/g salt | |||
| Would this salt be most useful for ice or heat packs? |
Part B: Calculating the Heat Capacity of a Calorimeter
| Trial 1 | Trial 2 | |
|---|---|---|
| Mass of calorimeter (Coffee cups and lid) | ||
| Mass of "cold" water | ||
| Initial temperature of "cold" water | ||
| Mass of hot water | ||
| Initial temperature of hot water | ||
| Final temperature of the system | ||
| Specific heat of water | 4.184 J/g∘C | 4.184 J/g∘C |
| q Lost by hot water | ||
| q Gained by cold water | ||
| Heat capacity of calorimeter | ||
| Average heat capacity of calorimeter |
| Trial 1 | Trial 2 | ||
|---|---|---|---|
| Time | Temperature | Time | Temperature |
| 0 | 0 | ||
| 10 | 10 | ||
| 20 | 20 | ||
| 30 | 30 | ||
| 40 | 40 | ||
| 50 | 50 | ||
| 60 | 60 | ||
| 70 | 70 | ||
Part C: Calculating the Specific Heat of Copper
| Trial 1 | Trial 2 | |
|---|---|---|
| Mass of copper shots used | ||
| Initial temperature of copper shots/copper wire | ||
| Final temperature of the system | ||
| Mass of water in calorimeter | ||
| Initial temperature of water in calorimeter | ||
| Specific heat of water | 4.184 J/g∘C | 4.184 J/g∘C |
| q Gained by water | ||
| Specific heat of copper (Assuming no heat lost to calorimeter) | ||
| Average specific heat of copper | ||
| Specific heat of copper (Using calorimeter specific heat from Part B) | ||
| Average specific heat of copper | ||
| If the specific heat of Cu is 0.386 J/g∘C, what is the % error from the above row? |
| Trial 1 | Trial 2 | ||
|---|---|---|---|
| Time | Temperature | Time | Temperature |
| 0 | 0 | ||
| 10 | 10 | ||
| 20 | 20 | ||
| 30 | 30 | ||
| 40 | 40 | ||
| 50 | 50 | ||
| 60 | 60 | ||
| 70 | 70 | ||
Post-Lab Questions
- According to your results, what salt in Part A would have been the best choice for use in a heat pack? In a cold pack? Defend your choice.
- Why is it not possible to reuse a heat pack in term of the chemistry?
- Compare the specific heat of water to the specific heat of metal in the table provided. Which would heat up faster (with less energy required)
- Why would metal make a poor ingredient in a heat pack?
- If there was a delay between measuring the initial temperature of a hot object and its transfer to the calorimeter, how would the heat capacity of the object be affected? How would the calculation of the heat capacity of the calorimeter be affected (too high, too low, or no affect)?
- If hot water from the test tube in Part C had accidentally dripped into the calorimeter, how would the calculation of the specific heat of the calorimeter be affected (too high, too low, or no affect)?