3: Measurements
- Page ID
- 548927
\( \newcommand{\vecs}[1]{\overset { \scriptstyle \rightharpoonup} {\mathbf{#1}} } \)
\( \newcommand{\vecd}[1]{\overset{-\!-\!\rightharpoonup}{\vphantom{a}\smash {#1}}} \)
\( \newcommand{\dsum}{\displaystyle\sum\limits} \)
\( \newcommand{\dint}{\displaystyle\int\limits} \)
\( \newcommand{\dlim}{\displaystyle\lim\limits} \)
\( \newcommand{\id}{\mathrm{id}}\) \( \newcommand{\Span}{\mathrm{span}}\)
( \newcommand{\kernel}{\mathrm{null}\,}\) \( \newcommand{\range}{\mathrm{range}\,}\)
\( \newcommand{\RealPart}{\mathrm{Re}}\) \( \newcommand{\ImaginaryPart}{\mathrm{Im}}\)
\( \newcommand{\Argument}{\mathrm{Arg}}\) \( \newcommand{\norm}[1]{\| #1 \|}\)
\( \newcommand{\inner}[2]{\langle #1, #2 \rangle}\)
\( \newcommand{\Span}{\mathrm{span}}\)
\( \newcommand{\id}{\mathrm{id}}\)
\( \newcommand{\Span}{\mathrm{span}}\)
\( \newcommand{\kernel}{\mathrm{null}\,}\)
\( \newcommand{\range}{\mathrm{range}\,}\)
\( \newcommand{\RealPart}{\mathrm{Re}}\)
\( \newcommand{\ImaginaryPart}{\mathrm{Im}}\)
\( \newcommand{\Argument}{\mathrm{Arg}}\)
\( \newcommand{\norm}[1]{\| #1 \|}\)
\( \newcommand{\inner}[2]{\langle #1, #2 \rangle}\)
\( \newcommand{\Span}{\mathrm{span}}\) \( \newcommand{\AA}{\unicode[.8,0]{x212B}}\)
\( \newcommand{\vectorA}[1]{\vec{#1}} % arrow\)
\( \newcommand{\vectorAt}[1]{\vec{\text{#1}}} % arrow\)
\( \newcommand{\vectorB}[1]{\overset { \scriptstyle \rightharpoonup} {\mathbf{#1}} } \)
\( \newcommand{\vectorC}[1]{\textbf{#1}} \)
\( \newcommand{\vectorD}[1]{\overrightarrow{#1}} \)
\( \newcommand{\vectorDt}[1]{\overrightarrow{\text{#1}}} \)
\( \newcommand{\vectE}[1]{\overset{-\!-\!\rightharpoonup}{\vphantom{a}\smash{\mathbf {#1}}}} \)
\( \newcommand{\vecs}[1]{\overset { \scriptstyle \rightharpoonup} {\mathbf{#1}} } \)
\( \newcommand{\vecd}[1]{\overset{-\!-\!\rightharpoonup}{\vphantom{a}\smash {#1}}} \)
\(\newcommand{\avec}{\mathbf a}\) \(\newcommand{\bvec}{\mathbf b}\) \(\newcommand{\cvec}{\mathbf c}\) \(\newcommand{\dvec}{\mathbf d}\) \(\newcommand{\dtil}{\widetilde{\mathbf d}}\) \(\newcommand{\evec}{\mathbf e}\) \(\newcommand{\fvec}{\mathbf f}\) \(\newcommand{\nvec}{\mathbf n}\) \(\newcommand{\pvec}{\mathbf p}\) \(\newcommand{\qvec}{\mathbf q}\) \(\newcommand{\svec}{\mathbf s}\) \(\newcommand{\tvec}{\mathbf t}\) \(\newcommand{\uvec}{\mathbf u}\) \(\newcommand{\vvec}{\mathbf v}\) \(\newcommand{\wvec}{\mathbf w}\) \(\newcommand{\xvec}{\mathbf x}\) \(\newcommand{\yvec}{\mathbf y}\) \(\newcommand{\zvec}{\mathbf z}\) \(\newcommand{\rvec}{\mathbf r}\) \(\newcommand{\mvec}{\mathbf m}\) \(\newcommand{\zerovec}{\mathbf 0}\) \(\newcommand{\onevec}{\mathbf 1}\) \(\newcommand{\real}{\mathbb R}\) \(\newcommand{\twovec}[2]{\left[\begin{array}{r}#1 \\ #2 \end{array}\right]}\) \(\newcommand{\ctwovec}[2]{\left[\begin{array}{c}#1 \\ #2 \end{array}\right]}\) \(\newcommand{\threevec}[3]{\left[\begin{array}{r}#1 \\ #2 \\ #3 \end{array}\right]}\) \(\newcommand{\cthreevec}[3]{\left[\begin{array}{c}#1 \\ #2 \\ #3 \end{array}\right]}\) \(\newcommand{\fourvec}[4]{\left[\begin{array}{r}#1 \\ #2 \\ #3 \\ #4 \end{array}\right]}\) \(\newcommand{\cfourvec}[4]{\left[\begin{array}{c}#1 \\ #2 \\ #3 \\ #4 \end{array}\right]}\) \(\newcommand{\fivevec}[5]{\left[\begin{array}{r}#1 \\ #2 \\ #3 \\ #4 \\ #5 \\ \end{array}\right]}\) \(\newcommand{\cfivevec}[5]{\left[\begin{array}{c}#1 \\ #2 \\ #3 \\ #4 \\ #5 \\ \end{array}\right]}\) \(\newcommand{\mattwo}[4]{\left[\begin{array}{rr}#1 \amp #2 \\ #3 \amp #4 \\ \end{array}\right]}\) \(\newcommand{\laspan}[1]{\text{Span}\{#1\}}\) \(\newcommand{\bcal}{\cal B}\) \(\newcommand{\ccal}{\cal C}\) \(\newcommand{\scal}{\cal S}\) \(\newcommand{\wcal}{\cal W}\) \(\newcommand{\ecal}{\cal E}\) \(\newcommand{\coords}[2]{\left\{#1\right\}_{#2}}\) \(\newcommand{\gray}[1]{\color{gray}{#1}}\) \(\newcommand{\lgray}[1]{\color{lightgray}{#1}}\) \(\newcommand{\rank}{\operatorname{rank}}\) \(\newcommand{\row}{\text{Row}}\) \(\newcommand{\col}{\text{Col}}\) \(\renewcommand{\row}{\text{Row}}\) \(\newcommand{\nul}{\text{Nul}}\) \(\newcommand{\var}{\text{Var}}\) \(\newcommand{\corr}{\text{corr}}\) \(\newcommand{\len}[1]{\left|#1\right|}\) \(\newcommand{\bbar}{\overline{\bvec}}\) \(\newcommand{\bhat}{\widehat{\bvec}}\) \(\newcommand{\bperp}{\bvec^\perp}\) \(\newcommand{\xhat}{\widehat{\xvec}}\) \(\newcommand{\vhat}{\widehat{\vvec}}\) \(\newcommand{\uhat}{\widehat{\uvec}}\) \(\newcommand{\what}{\widehat{\wvec}}\) \(\newcommand{\Sighat}{\widehat{\Sigma}}\) \(\newcommand{\lt}{<}\) \(\newcommand{\gt}{>}\) \(\newcommand{\amp}{&}\) \(\definecolor{fillinmathshade}{gray}{0.9}\)- Learn how to make measurements in the chemistry laboratory.
- Learn how density can be used to provide evidence for the identity of an object.
INTRODUCTION
In the following experiment, you will be make length, mass, and volume measurements. You will use these to calculate the density of a piece of metal and determine it's identity.
1) There are no significant hazards in this experiment.
PROCEDURE
*Always use only pen- no pencils, no whiteout*
- On a new page, write the date (upper right) and Title (middle) of your experiment. (Your pages should already be numbered.)
- Write the header "Group Members" and list the names of each member of the group.
- Write the header "Length Measurement"
- Obtain a small scrap of paper for each group member.
- Write a short, straight pencil line in your lab notebook.
- One at a time, using the centimeters side of your ruler, record the length of that line on your scrap of paper being careful not to let the other group member see it.
- Measurements should always be recorded estimating one digit beyond the markings shown on the device. For a centimeter ruler, this would be "X.XX cm". Your instructor will have likely gone over this with you, but if not, here is a video explaining the process.
- Next, on the count of 3, show each other your measurements. First, double check to see that each of your measurements are recorded to the second decimal place and they are the same, except for the last digit. (If you have any questions, call your instructor over.)
- Record those three different measurements in your lab notebook.
- Write the header "Density Experiment".
- Obtain a piece of metal, called "shot" from the lab supplies.
- Write down some observations about the piece of metal.
- This piece of metal is one of Aluminum, Zinc, or Tin.
- Write a hypothesis about the identity of the metal.
- Watch this video about using density to determine a metal's identity.
- Next, you will test your hypothesis by determining the density of your piece of metal.
- Density is the Mass / Volume, which is unique for each substance.
- Measure and record the mass of the metal on a laboratory balance.
- Make sure the doors are closed and set the balance to zero (Tare).
- Open the door and place the metal on the balance pan.
- Record all of the digits shown on the balance and the unit.
- Measure the volume by displacement. You will need to...
- Obtain a 10-mL graduated cylinder
- Pour a few milliliters of water into the cylinder.
- Observe the surface of the water closely, and write down observations in your lab notebook. Is it straight across? What shape is it?
- Record the initial volume with unit, estimating one digit beyond the marking shown (X.XX mL). (When reading the volume of water in chemistry glassware, we always read at the bottom of the "meniscus" curve of water. Sometimes it can be difficult to see. You can hold a colored piece of paper up behind it. Here's a very short video with another technique to make it easier to see.)
- Drop the piece of metal in, then tap the side a few times with your pen to release any bubbles.
- Last, record the final volume, as above.
- Now subtract the initial volume from the final volume and calculate the density.
- Compare your density to those in Table 1 below to find your metal's identity.
- This Scientific investigation was set up for you, what were your Dependent, Independent, and Confounding Variables? Fill out Table 2 in your notebook.
- Write a 2 - 4 sentence conclusion about your experiment.
- Write the header "Member Contributions", write down the contributions made by each group member.
- Fill out the Table of Contents with this experiment's Page Numbers, Title, and Date.
- Scan and upload to the assignment on Canvas.
| Metal | Density |
|---|---|
| Aluminum | 2.6 g/mL |
| Tin | 5.8 g/mL |
| Zinc | 7.1 g/mL |
| Silver | 10.5 g/mL |
| Gold | 19.3 g/mL |