chemistry- jib topic 1 matter and measurement

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Page 1: Chemistry- JIB Topic 1 Matter and Measurement
Page 2: Chemistry- JIB Topic 1 Matter and Measurement

Chemistry – science that deals with matter and the changes that matter undergoes

Macroscopic – all around us

Microscopic – air, molecules, etc

Page 3: Chemistry- JIB Topic 1 Matter and Measurement

Scientific Problem Solving3 Step Process

1. state problem and make observations (qualitative vs. quantitative)

2. formulate a possible solution3. perform experiments to test hypothesis

Page 4: Chemistry- JIB Topic 1 Matter and Measurement

Theory vs. LawTheory – gives a universally accepted

explanation of the problem

Law – state what general behavior is observed that occurs normally

Page 5: Chemistry- JIB Topic 1 Matter and Measurement

States of MatterAll matter has 2 characteristics

Has mass and occupies space

3 types: solid, liquid, gas

Solids – definite shape and volume; packed tightly together; vibrate gently around fixed positions

Liquids – no shape of own; fill container; definite volume; particles are free to move

Gases – no shape or definite volume; particles spread apart; filling all space in container

Page 6: Chemistry- JIB Topic 1 Matter and Measurement

Physical and Chemical Properties and Changes

Physical Property: color, odor, density, hardness, solubility, melting point, boiling point

Physical Change: chemical composition always remains the same. Ex. Phase changes (2 less known ones are sublimation (solid to gas) and deposition (gas to solid)

Chemical Property: reacts with acid, reacts with base, oxidation and reduction

Chemical Change: won’t go back to original substance. Ex. combustion

Page 7: Chemistry- JIB Topic 1 Matter and Measurement

E, C, MElement – pure substance that cannot be broken

down any further…..single substance from periodic table

Compound – pure substance that cannot be broken down by physical means; formed when elements bond together….have fixed composition

Mixture – varying composition and is made up of a number of pure substances.Homogeneous – uniform compositionHeterogeneous – varying composition

Page 8: Chemistry- JIB Topic 1 Matter and Measurement

MeasurementScientific Notation

The number of places the decimal point has moved determines the power of 10

Decimal moves left = positive powerDecimal moves right = negative power

42000 = 4.2 x 104

0.00012 = 1.2 x 10-4

Page 9: Chemistry- JIB Topic 1 Matter and Measurement

SI Units and prefixes

Base Quantity Unit Symbol

Mass Kilogram kg

Length Meter m

Time Second s

Amt. of Substance

Mole mol

Temperature Kelvin K

Page 10: Chemistry- JIB Topic 1 Matter and Measurement

Prefix Symbol Meaning

Giga G 109

Mega M 106

kilo k 103

deci d 10-1

centi c 10-2

milli m 10-3

micro μ 10-6

nano n 10-9

pico p 10-12

Page 11: Chemistry- JIB Topic 1 Matter and Measurement

3 scales for temperatureCelsiusKelvinFahrenheit

Celsius to Kelvin (°C + 273)Kelvin to celsius (K – 273)Celsius to fahrenheit (°C * 9/5) + 32Fahrenheit to celsius (°F – 32) * 5/9

Page 12: Chemistry- JIB Topic 1 Matter and Measurement

Derived UnitsAll other units can be derived from base

quantitiesExamples:

1. Volume: unit is length3

Common units are L or mL (how much is a cm3?)

1.00 L = 1000 mL = 1000 cm3 = 1.00 dm3

2. Density = mass/volume

Page 13: Chemistry- JIB Topic 1 Matter and Measurement

UncertaintyWhen reading the scale on a piece of lab

equipment, there is always a degree of uncertainty

Estimate must be made to record the final digitThis “uncertain” digit is recorded by using the

+/- scale

Rounding – don’t round until the end of a calculation

Page 14: Chemistry- JIB Topic 1 Matter and Measurement

Significant FiguresRemember the Atlantic and Pacific rule

In Calculations Multiplying and dividing: limit answer to least

number of sig figs used Adding and subtracting: limit answer to same

number of decimal places that appear in the original data with fewest number of decimal places

Page 15: Chemistry- JIB Topic 1 Matter and Measurement

Accuracy vs. Precision

Accuracy – relates to how close the measured value is to the actual value of the quantity

Precision – how close 2 or more measurements of the same quantity are to one another

Page 16: Chemistry- JIB Topic 1 Matter and Measurement

Percent ErrorData that is derived from experiments will

often differ from the accepted, published, actual value

Common way of expressing accuracy is: | Actual – Calculated | x 100

Actual