Introduction
Welcome to CHEM 162
Brendan Stamper
brendan.stamper@seattlecolleges.edu
206.683.1139
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Outline
Go over syllabus
 Introduction to lab section
 Start chapter 10
 Discuss chapter 10 project

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Lab overview
Held on Wednesdays (typically the last 2-3 hours of class)
 Lab attendance is mandatory and there are no make up labs

◦ Please contact me if you miss a lab due to illness or some other
emergency. We can work something out but it will not be for
full credit since part of the credit is actually doing the lab

Things to consider
◦ Most of the labs take about 90 minutes
◦ While a few do require more time, it will take more time if you
do not come prepared
◦ Patience and attention to detail will help you do well in the lab

There are 8 graded labs, each consisting of . . .
◦ Preparation (prelab) work
◦ Lab work
◦ Postlab work
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Prelab

Grading prep work
◦ I will have a checklist and check your notebook at
the start of class
◦ Necessary information should be filled out before
class begins and must be signed off by the
instructor before you start working (more on
this later)
◦ If I see you doing pre-lab work in lab (i.e. not
done before you get here) you will not get credit

Do not start early
◦ The first 5-10 minutes are for me to provide
useful hints and information
◦ If you’re setting up, you’re not paying attention
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During lab
No food or drinks, ever
Personal items should be stored underneath
bench-tops
 Protective eyewear should be worn at all times
until everyone is done (or I say so)


◦ Wearing them on your neck, on your forehead, on
your hair, or putting them on the bench does not
count as wearing them
◦ They may be uncomfortable, leave marks, and look
funny, but the alternative is blindness. So
keep…them…on!

One reminder is all I will give. After that, you will
lose points each time I see it
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Postlab

You are welcome (and I encourage you) to stay when you
are done
◦ Work on calculations
 Calculations should always include correct significant figures and units
 You need to show one sample for each different type of calculation
 If you repeat a calculation two or three times you do not need to show
the work for every individual calculation (unless you want to)
◦ Ask questions
◦ Check answers

Before you leave, show me your notebook (~5 points)
◦ I will have a checklist and check your notebook at the end of
class
◦ Coming back after class does not count because I don’t know if
you actually did it or just copied it
◦ Necessary information should be filled out before leaving (i.e.
calculations, tables and figures)
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Grading

The lab section is worth 120 out of the
total 460 points for the class (~25%)
◦ Lab work
 80 points
 10 points per lab
◦ Lab reports
 40 points
 5 points per report
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Lab work grade breakdown

Prelab (~5 points)
◦
◦
◦
◦

Name/date/lab name
Answers to pre-lab questions (if any)
Purpose or objective of the lab
Summary of the procedures (at least one high quality paragraph
outlining the lab)
During lab
◦ Points will be deducted for not following safety rules and lab practices
(e.g. -2 points for not wearing proper attire)

Post lab (~5 points)
◦ Notebooks will be checked for the following:




Sig figs and units
Completed data tables
Calculations (show work for credit)
Completed postlab questions
◦ Points will be deducted for not cleaning your bench or shared
workspaces
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Lab report grade breakdown
Lab reports are due at the next lab meeting
(typically one week)
 They are due at the start of class
 One lab report per group
 5 points per report

◦
◦
◦
◦
◦
1 point for the Abstract
1 point for the Introduction & Methods sections
1 point for the Results section
1 point for the Discussion section
1 point for overall report
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More on the lab notebook:
General information

You may use any notebook you like (carbon pages
are not required) as long as it is
◦ Dedicated to lab (not in your normal note-taking
notebooks)
◦ Bound (absolutely no loose pages)
If it meets the above specifications, feel free to
use the same notebook you used in CHEM161
 The notebook is your record of what you did and
what you observed
 Never, ever, ever write anything on scrap paper or
the lab handouts. Everything goes into the
notebook

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More on lab notebook:
Procedure summary
This prelab component not only helps you prepare for the
lab, but also gives you a head start on the methods section of
your lab report
 Sample full credit procedure summary (shows you read and
understand the lab):

“In this lab we will do four different acid-base titrations:
strong/strong, strong acid/weak base, strong base/weak acid, and
weak/weak. First, we will set up the titration apparatus and
prepare the LabPros to collect titration data. Next, we will
measure the volume of an individual drop from the burette.
Finally, we will carry out the four titrations using different
combinations of acids and bases and record the titration curves
using the LabPro. After the titrations are done, we will dispose
of the waste products in the appropriate container.”

Sample zero credit summary:
“We will do lots of different titrations.”
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Precision vs Accuracy

Precision
◦ reproducibility or repeatability

Accuracy
◦ degree of closeness of a measured value to its actual value (i.e.
getting the “right” answer)

Data may be
◦ Precise, but not accurate (good, not great)
◦ Precise and accurate (best)
◦ Not precise and not accurate (worst)

In general, precision is more important than accuracy
◦ Accuracy problems can be fixed (calibrations, changes to
method, etc)
◦ Precision problems can be difficult to track down and fix
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