MSC 180 - Water Analysis

Instructor: Jacqui Jenkins

Office: S204D

Email: jjenkins@cfcc.edu

Phone: 362-7405

Laboratory Safety

Safety Requirements

Safety Equipment

Eyewash & Shower First Aid Kit

Fire & Fire Safety

Fire Blanket Fire Extinguisher

1. Water

2. CO2

3. Dry-Powder

4. Halon

Safety Equipment

MSDS Material Safety Data Sheets

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

The Metric System

Length Meter

Mass Kilogram

Volume Liter

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

The Metric System - Length

1 micrometer (µm) = 0.000001 meter 1 millimeter (mm) = 0.001 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

The Metric System – Weight (Mass)

1 microgram (µg) = 0.000001 gram 1 milligram (mg) = 0.001 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

The Metric System - Volume

1 microliter (µL) = 0.000001 liter 1 milliliter (mL) = 0.001 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

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

The Metric System

Temperature Celsius (°C) Kelvin (K)

Absolute zero 0 K -273.15 °C -459.67 F

Conversion

Dimensional Analysis Factor-Label Method

Conversion

Metric English Equivalents 1 cm = 0.3937 in. 1 m = 3.281 ft = 39.37 in. 1 km = 0.6214 mile 1 L = 0.2646 gal 1 kg = 2.204 lbs

Conversion

K = °C + 273

°C = 5/9(°F - 32)

°F = 9/5(°C +32)

The Metric System

Density Mass per unit volume D = M/V Mass in grams Volume in cubic centimeters

g/cm3

Lab Procedures

Precision 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

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.

Significant Figures

Cardinal Rule: A final result should never contain any more

significant figures than the least precise data used to calculate it.

Significant Figures

General Rules:1. The concept applies only to measured quantities.2. All significant figures are counted from the first

nonzero digit.3. All confined zeros in a number are significant.4. Zeros that are both to the right of the decimal

point and to the right of nonzero digits are significant.

5. The answer in an addition or subtraction problem must be rounded off to the first column that has a doubtful digit.

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.

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

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?

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

Lab Procedures

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