Honors Chemistry

Honors Chemistry

Chapter 1

The Study of Change

11 ndash 12 Chemistry

bull The study of matter and the changes it undergoes

bull Structure and properties of matter

bull Macroscopic vs Microscopic

bull Structure (microscopic) determines properties (macroscopic)

13 Scientific Method

bull Systematic approach to research

bull Based on data gathered by observationbull Qualitative ndash general observationsbull Quantitative ndash numeric data

bull Evolution of ideasbull Hypothesis ndash tentative explanation testablebull Theory ndash unifying principle that explains

observationsbull Scientific Law ndash mathematical relationship

14 Classification of Matter

bull Matter ndash anything with mass and volumebull Substance ndash matter with definite composition

and distinct propertiesbull Element ndash cannot be separated into simpler

substances (ie only one type of atom present)bull Examples aluminum gold sulfur oxygen neonbull Compound ndash two or more elements chemically

combined in fixed proportionsbull Examples water sulfuric acid rust baking soda

14 Classification of Matter

bull Mixture ndash combination of two or more substances which retain their identities

bull Homogeneous mixture ndash composition of mixture is uniform throughout

bull Examples saltwater air metal alloysbull Heterogeneous mixture ndash composition is

not uniform phase boundariesbull Examples salt and pepper oil and water

salad dressing

14 Classification of Matter

15 States of Matter

solid liquid gas

melting

freezing

vaporizing

condensing

sublimation

deposition

16 Properties of Matter

bull Physical propertybull can be observed without changing the identity of

the substance

bull Physical changebull remains the same substance

bull Extensive propertybull Depends only on the amount of matter present

bull Intensive propertybull Depends on the type of matter present

16 Properties of Matter

bull Chemical propertybull Property involving reactions with other substances

bull Chemical changebull New substance is produced

bull Classify the following propertiesbull Color mass flammability solubility density

bull Classify the following changesbull Rusting cutting melting burning dissolving

17 SI Units

bull Systegraveme Internationale drsquoUnites

bull International System of Units

Base quantity Name Symbol

length meter m

mass kilogram kg

time second s

electric current ampere A

temperature kelvin K

amount of substance mole mol

luminous intensity candela cd

17 SI Conversions

Factor Name Symbol

1024 yotta Y

1021 zetta Z

1018 exa E

1015 peta P

1012 tera T

109 giga G

106 mega M

103 kilo k

102 hecto h

101 deka da

Factor Name Symbol

10-1 deci d

10-2 centi c

10-3 milli m

10-6 micro micro

10-9 nano n

10-12 pico p

10-15 femto f

10-18 atto a

10-21 zepto z

10-24 yocto y

17 SI Conversions

unitdahk mcdMGT pn

1 decimal place3 decimal places 3 decimal places

Some Practice

173 cm = ______ m0173 0025 kg = ______ mg25 000

587 nm = __________ cm0000 058 7

Multiply number of decimal places by the dimensionality of the unit

0986 dm3 = ______ cm3986

17 Derived Units

bull Mathematical combinations of base unitsbull Area A=lw mm = m2

bull Volume V = lwh m m m = m3

bull dm3 = Liter cm3 = mL

bull Density = mV kgm3 gcm3 gmL

bull Mass vs Weightbull Mass = amount of matter = kgbull Weight = force of gravity = N

17 Temperature Scales

Boiling PointBoiling Point

Freezing PointFreezing Point

Absolute ZeroAbsolute Zero

Fahrenheit

Coldest tempin lab = 0oF

Human bodytemp = 100oF

32oF

212oF

-460oF

Celsius

0oC

100oC

-27315oC

Kelvin

27315 K

37315 K

0 K

17 Temperature Conversions

bull Celsius-Kelvin offset by 27315o

bull K = oC + 27315bull oC = K ndash 27315

bull Celsius-Fahrenheitbull Offset by 32oFbull Different sized degrees 9Fo = 5Co

bull oC = 59 (oF - 32)bull oF = 95 oC + 32bull Convert 986oF to oC and to K

18 Scientific Notation

bull m x 10n

bull 1 le m lt 10

bull Exponentiation multiply exponents

bull Multiplication Add exponents

bull Division Subtract exponents

bull AdditionSubtraction must have same exponent

18 Significant DigitsDigits which were actually measured as opposed to placeholder zeroes

Considerhow long is the blue rectangle

1 2 3 4 5 cm

Read 2 cm Estimate the next digit 24 cm plusmn 01 cm

Letrsquos use a better ruler

Now how long is the rectangle

243 cm plusmn 001 cm

measurementx

uncertainty in measurement

x

Implied plusmn1 on last digit of all measurements unless told otherwise

18 Significant Digits

bull Rules of thumb to deal with calculations involving significant digits

bull AdditionSubtractionbull Round to the decimal place of the least precise

value

bull MultiplicationDivisionbull Round to the number of digits of the least precise

value

bull Answers must be rounded properly

18 Relative Error

bull Compare uncertainty to measurementbull x

RE = ------ x

bull Often expressed as a percentbull With laboratory data x is found by comparing

experimental result to theoretical expectationsbull | xth ndash xexp |

RE = --------------- xth

18 Accuracy and Precision

bull Accuracybull how close a measurement is to the correct valuebull How close were you to the bullrsquos eye

bull Precisionbull how closely a set of values agree with each otherbull Were your shots clustered or scattered

bull Letrsquos measure the bp of water 3 timesbull Accurate but not precise 96oC 101oC 104oCbull Precise but not accurate 572oC 568oC 571oC

19 Dimensional Analysis

bull Technique for solving problems by treating units of measure as algebraic quantities

bull Set up conversion factors

bull 18 in = __________ ft

bull We know 1 ft = 12 in

bull 18 in 1 ft------- x -------- = 1 12 in

15 ft

19 Dimensional Analysis

bull Convert the speed of light (300 x 108 ms) to miles hour

bull 300 x 108 m 1 km 1 mile 3600 s------------------ x ---------- x ---------- x -------- 1 s 1000 m 16 km 1 hr

bull = 68 x 108 mihr

bull 2 sig dig because of km ndash mile conversion

bull That wasnrsquot so bad was it