1. Instructor: Jacqui Jenkins
MSC Water Analysis
Instructor: Jacqui Jenkins
Office: S204D
Phone:

2. Laboratory Safety Safety Requirements Go through each of 20
Use examples of past stories of lab safety gone wrong

3. Safety Equipment Eyewash & Shower First Aid Kit
If you get something from the lab in your eye—
GET IT OUT IMMEDIATELY!
Don't wait until lunch or after class!
Run some water through the eyewash fountain before you use it.
Retract your eyelid (hold it open);
Don’t squint your eyes
this restricts water access.
Run fresh water over your eye for several minutes.
If the water at your school is COLD
Wash your eyes INTERMITTENTLY
Rest in between rinses.
Seek medical attention

4. Fire & Fire Safety Fire Blanket Fire Extinguisher Water CO2 Dry-Powder
Halon
Classes of Fires
Fire Triangle
Fuel
Oxygen
Ignition source

5. Safety Equipment MSDS Material Safety Data Sheets What are they?
What information do they provide?
Use examples in the lab; where are they located?

6. The Metric System Decimal system of measurement Base of 10 History
France, 1791
Adopted by scientists throughout that world, 1960
International System (le Système International) SI
US, Liberia, and Myanmar (Burma)
Adoption of Metric system in the US
Since 1791, it has been adopted by most countries of the world.
Liberia = west coast of Africa
Burma = Asia

7. The Metric System
Length
Meter
Mass
Kilogram
Volume
Liter
Base units

8. The Metric System - Prefixes
micro = µ = one-millionth = 10-6
milli = m = one-thousandth = 10-3
centi = c = one-hundredth = 10-2
deci = d = one-tenth = 10-1
deka = dk = ten times = 101
hecto = h = hundred times = 102
kilo = k = thousand times = 103
mega = M = million times = 106
Prefixes commonly used in the metric system
Most common shown in red

9. The Metric System - Length
1 micrometer (µm) = meter
1 millimeter (mm) = meter
1 centimeter (cm) = 0.01 meter
1 decimeter (dm) = 0.1 meter
1 dekameter (dkm) = 10 meters
1 hectometer (hm) = 100 meters
1 kilometer (km) = 1000 meters

10. The Metric System – Weight (Mass)
1 microgram (µg) = gram
1 milligram (mg) = gram
1 centigram (cg) = 0.01 gram
1 decigram (dg) = 0.1 gram
1 dekagram (dkg) = 10 grams
1 hectogram (hg) = 100 grams
1 kilogram (kg) = 1000 grams
What’s the difference between ‘weight’ and ‘mass’?
mass = quantity of matter contained in an object
weight = a relation of mass and gravity; weighing an object is finding its mass here on Earth
But note that a 5 kg bag of flour still weighs (in the everyday sense of the word) 5 kg on the moon, and if a recipe calls for 200 g of flour, you'd still use 200 g of flour when baking on the moon. And that 200 g of flour is the same amount (in every sense of the word) of flour on the moon as on Earth, but it weighs (in the technical sense) less, in that it doesn't “feel” as heavy when you lift it on the moon.

11. A US cent weighs exactly 2.5 g, while the nickel weighs exactly 5 g.

12. The Metric System - Volume
1 microliter (µL) = liter
1 milliliter (mL) = liter
1 centiliter (cL) = 0.01 liter
1 deciliter (dL) = 0.1 liter
1 dekaliter (dkL) = 10 liters
1 hectoliter (hL) = 100 liters
1 kiloliter (kL) = 1000 liters

13. 1012 microphones = 1 megaphone
106 bicycles = 2 megacycles
2000 mockingbirds = 2 kilomockingbirds
10 cards = 1 decacards
10¯6 fish = 1 microfiche
454 graham crackers = 1 pound cake
1012 pins = 1 terrapin
10 rations = 1 decoration
10 millipedes = 1 centipede
3 1/3 tridents = 1 decadent
10 monologs = 5 dialogues
2 monograms = 1 diagram
8 nickels = 2 paradigms
2 snake eyes = 1 paradise
2 wharves = 1 paradox
10¯6 phones = 1 microphone
106 phones = 1 megaphone
10¯2 mental = 1 centimental
10¯1 mate = 1 decimate
10¯12 boos = 1 picoboo

14. The Metric System Temperature Absolute zero Celsius (°C) Kelvin (K)F

15. Conversion
Dimensional Analysis
Factor-Label Method

16. Conversion Metric English Equivalents 1 cm = 0.3937 in.
1 m = ft = in.
1 km = mile
1 L = gal
1 kg = lbs

17. Conversion
K = °C + 273
°C = 5/9(°F - 32)
°F = 9/5(°C +32)

18. The Metric System Density Mass per unit volume D = M/V Mass in grams
Volume in cubic centimeters
g/cm3

19. Lab Procedures Precision Accuracy Reproducibility
Check by repeated measurements
Poor precision results from poor techniques
Accuracy
Correctness
Check by using a different method
Poor accuracy results from procedural or equipment flaws

20. A dartboard analogy is often used to understand the difference between accuracy and precision. Imagine a person throwing darts, trying to hit the bullseye. The closer the dart hits to the bull's-eye, the more accurate the tosses are. If the person misses the dartboard with every throw, but all of their shots land close together, they can still be very precise but not accurate.
Here's another example: The TV weather forecaster says that it will be between 40 and 50 degrees today. The actual reading turns out to be 43. Thus, the forecast was accurate, but not very precise. For tomorrow, the forecast is degrees at 4 PM. It turns out to be degrees. This forecast was very precise, but completely inaccurate.
The precision of an instrument reflects the number of significant digits in a reading;
The accuracy of an instrument reflects how close the reading is to the 'true' value measured.
Note that an accurate instrument is not necessarily precise, and instruments are often precise but far from accurate.
For example, you might read out time right down to the second, even though you know your watch is one minute slow. This reading is precise, but not accurate.
It makes little sense to quote values to high precision beyond the expected accuracy of the measurement. Without stating the estimated accuracy, such a reading cannot be used in serious computations. Worse, even by quoting the time down to the second, you have implied some accuracy which you cannot justify.

21. Significant Figures
The precision of an instrument reflects the number of significant figures in a reading
Micro-balance versus bathroom scale
The number of significant figures in a lab measurement is the number of digits that are known accurately, plus one that is uncertain or doubtful.

22. Significant Figures Cardinal Rule:
A final result should never contain any more significant figures than the least precise data used to calculate it.

23. Significant Figures General Rules:
The concept applies only to measured quantities.
All significant figures are counted from the first nonzero digit.
All confined zeros in a number are significant.
Zeros that are both to the right of the decimal point and to the right of nonzero digits are significant.
The answer in an addition or subtraction problem must be rounded off to the first column that has a doubtful digit.

24. Rounding
If a calculation yields a result that would suggest more precision than the measurement from which it originated, rounding off to the proper number of significant figures is required.

25. Rounding Rules of Rounding:
If the digit following the last significant figure is greater than 5, the number is rounded up to the next higher digit
If the digit following the last significant figure is less than 5, the number is rounded off to the present value of the last significant figure
If the digit following the last significant figure is exactly 5, the number is rounded off to the nearest even digit

26. Labware Section 2 of the handbook
These will be displayed for the rest of the week, then returned to their respective places for the rest of the semester
What is it?
What is it used for?
List of all labware to be used

27. Lab Procedures Recording Data/Lab Notebooks Ink Never rip out pages
Never erase data; cross out mistakes
Record all information, no matter how trivial
Be specific
Check all calculations
And, obviously, BE NEAT
Guidelines
each company has its own procedure for data entry

28. Lab Procedures Weighing/Balances
Most important tool in a chemistry lab
Used to determine the mass of an object
Triple-beam balance
Analytical balance