MSC 180 – Water AnalysisMSC 180 – Water AnalysisInstructor: Jacqui Jenkins DeganOffice Hours: Tuesday & Thursday1300-1500

Friday0800-0850

Safety EquipmentSafety EquipmentEyewash & ShowerFirst Aid Kit

Fire & Fire SafetyFire & Fire SafetyFire BlanketFire Extinguisher

◦Water◦CO2

◦Dry-Powder◦Halon

Safety EquipmentSafety EquipmentMSDS

◦Material Safety Data Sheets

The Metric SystemThe Metric SystemDecimal system of measurementBase of 10History

◦France, 1791◦Adopted by scientists throughout the

world, 1960◦International System (le Système

International) SI

Calculation ErrorsCalculation ErrorsGimli Glider

Mars Climate Orbiter

Medical Mishaps

The Metric SystemThe Metric System

BASE UNITSMeterKilogramSecondKelvinMoleAmpereCandela

10n Prefix Decimal Articulation1024 yota- 1 000 000 000 000 000 000 000 000 Septillion1021 zeta- 1 000 000 000 000 000 000 000 Sextillion1018 exa- 1 000 000 000 000 000 000 Quintillion1015 peta- 1 000 000 000 000 000 Quadrillion1012 tera- 1 000 000 000 000 Trillion109 giga- 1 000 000 000 Billion106 mega- 1 000 000 Million103 kilo- 1 000 Thousand102 hecta- 100 Hundred101 deca- 10 Ten100 ---------- 1 One10-1 deci- 0.1 Tenth10-2 centi- 0.01 Hundredth10-3 milli- 0.001 Thousandth10-6 micro- 0.000 001 Millionth10-9 nano- 0.000 000 001 Billionth10-12 pico- 0.000 000 000 001 Trillionth10-15 femto- 0.000 000 000 000 001 Quadrillionth10-18 atto- 0.000 000 000 000 000 001 Quintillionth10-21 zepto- 0.000 000 000 000 000 000 001 Sextillionth10-24 yocto- 0.000 000 000 000 000 000 000 001 Septillionth

The Metric System - The Metric System - LengthLength1 micrometer (µm) = 0.000001

meter1 millimeter (mm) = 0.001 meter1 centimeter (cm) = 0.01 meter1 decimeter (dm) = 0.1 meter1 dekameter (dkm) = 10 meters1 hectometer (hm) = 100 meters1 kilometer (km) = 1000 meters

The Metric System – Weight The Metric System – Weight (Mass)(Mass)1 microgram (µg) = 0.000001 gram1 milligram (mg) = 0.001 gram1 centigram (cg) = 0.01 gram1 decigram (dg) = 0.1 gram1 dekagram (dkg) = 10 grams1 hectogram (hg) = 100 grams1 kilogram (kg) = 1000 grams

The Metric SystemThe Metric SystemTemperature

◦Celsius (°C)◦kelvin (K)

Absolute zero◦0 K◦-273.15 °C◦-459.67 F

Step Mental Arithmetic

1. Add 40 100 + 40 = 140

2. Multiply by 2 2 x 140 = 280

3. Subtract 10% 280 – 28 = 252

4. Subtract 40 to obtain final answer

252 – 40 = 212 degrees Fahrenheit

K = °C + 273°C = 5/9(°F -

32)°F = (9/5x°C)

+32 Step Mental Arithmetic

1. Add 40 32 + 40 = 72

2. Multiply by 0.5

0.5 x 72 = 36

3. Add 10% 36 – 3.6 = ~40

4. Subtract 40 to obtain final answer

40 – 40 = degrees Celsius

ConversionConversionDimensional Analysis

◦Factor-Label Method

← Conversion to English Units Conversion to SI Units →

English Units ←Divide by Multiply by→ SI Units

Length

Inches (in) 25.4 Millimeters (mm)Feet (ft) 0.305 Meters (m)

Yards (yd) 0.914 Meters (m)Miles (mi) 1.61 Kilometers (km)

Area

Square Inches (in2) 645.2 Square Millimeters (mm2)Square Feet (ft2) 0.093 Square Meters (m2)Square Yard (yd2) 0.836 Square Meters (m2)Square Miles (mi2) 2.59 Square Kilometers (km2)

Volume

Fluid Ounces (fl oz) 29.57 Milliliters (mL)Gallon (gal) 3.785 Liters (L)

Cubic Feet (ft3) 0.028 Cubic Meters (m3)Cubic Yard (yd3) 0.765 Cubic Meter (m3)

Note: All volumes greater than 1000 Liters should be in Cubic Meters (m3)Mass

Ounces (oz) 28.35 Grams (g)Drams (ℨ) 4.0 Grams (g)Grains (G) 0.0667 Grams (g)

Pounds (lb) 0.4536 Kilograms (kg)Short Ton (T) – 2000 lb 1016.05 Metric Ton/Megagrams (t/Mg)Short Ton (T) – 2000 lb 907.185 Kilograms (kg)

Temperature

Fahrenheit (°F) ← (1.8×°C)+32 (°F-32)/1.8 → Celsius (°C)Celsius (°C) °C + 273.15 Kelvin

Illumination

Lamberts (L) 0.3183 Candela per Square Meter (cd/cm2)

The Metric SystemThe Metric SystemDensity

◦Mass per unit volume◦D = m/V◦Mass in grams◦Volume in cubic centimeters

◦g/cm3

Lab ProceduresLab ProceduresPrecision

◦ 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 FiguresSignificant FiguresThe 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 FiguresSignificant FiguresCardinal Rule:

◦A final result should never contain any more significant figures than the least precise data used to calculate it.

Significant FiguresSignificant Figures

General Rules:The concept applies only to

measured quantities.

Adding & Subtracting:◦Decimal places are important:

500.5 + 37.222 = 537.722Sig figs = 537.7

Multiplying & Dividing:◦Total significant figures are important:

15.41 x 3.2 = 49.312Sig figs = 49

RoundingRoundingIf 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.

RoundingRoundingRules 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

◦When the digit is exactly 5, look to the digit preceding the 5: If the preceding digit is odd, round up. If the preceding digit is even, round down.