Introduction to essential skills you will need to use throughout the year

The Metric & SI System SI Base Units and Derived units Taking measurements Uncertainty Significant figures Scientific Notation

Dimensional Analysis (Factor conversions) Algebra Review Logarithms The Quadratic Formula Calculator tips

MEASUREMENTSMEASUREMENTS CALCULATIONSCALCULATIONS+ x EE – ⁼ ⁄

METRIC SYSTEM

TOOLS UNCERTAINTY

SIGNIFICANT DIGITS

SCIENTIFIC NOTATION

DIMENSIONAL ANALYSIS

Used in . . .

LOGARITHMS

GRAPHING Y= MX + B

QUADRATIC EQUATIONSI

UNITS

Chemistry Essential Skills

Every measurement consists of two parts:

Part 1Part 1 -- numbernumber Part 2Part 2 -- unitunit

Examples:Examples: 2020 gramsgrams

6.63 x 106.63 x 10-34-34 Joule·secondsJoule·seconds

Base unitsBase units 7 fundamental (base) units of measurement in the SI

system, from which all other units are derived. Example: Length; measured in meters (m)

Derived unitsDerived units All other units that are expressions of one or more of

the base units. Example: Volume = l x w x h (rectangular object) = cm x cm x cm = cm3 = 1mL

Physical Quantity Base Unit Abbreviation

Mass kilogram kg

Length meter m

Time second s

Temperature Kelvin K

Electric Current Ampere A

Amount of Substance mole mol

Luminous I ntensity candela cd

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ggmmLL 1010-1-1 1010-2-2 1010-3-3101011101022101033

BaseBaseunitunit

deci centi millidekahectokilo micro nano pico

1010-6-6 1010-9-91010-12-12

Metric Prefixes indicate the “size” of some measured number in relation to the base unit (g, L, m, s…)

The prefixed unit = (Base unit) x some factor of 10.

Ex. 1 kg 1 kg = 1g x 103 = 1000g1000g

Prefix Symbol Multiplier Exponential yotta Y 1,000,000,000,000,000,000,000,000 1024 zetta Z 1,000,000,000,000,000,000,000 1021 exa E 1,000,000,000,000,000,000 1018 peta P 1,000,000,000,000,000 1015 tera T 1,000,000,000,000 1012 giga G 1,000,000,000 109

mega M 1,000,000 106 kilo k 1,000 103

hecto h 100 102 deca da 10 101

BASE UNIT 1 100 = 1deci d 0.1 10¯1 centi c 0.01 10¯2 milli m 0.001 10¯3

micro µ 0.000001 10¯6 nano n 0.000000001 10¯9 pico p 0.000000000001 10¯12

femto f 0.000000000000001 10¯15 atto a 0.000000000000000001 10¯18

zepto z 0.000000000000000000001 10¯21 yocto y 0.000000000000000000000001 10¯24

The Scale of the Universe

http://htwins.net/scale/index.html

ggmmLL

1010-1-1 1010-2-2 1010-3-3101011101022101033

BaseBaseunitunit

deci centi millidekahectokilo micro nano pico

1010-6-6 1010-9-91010-13-13

Example #1: Convert 18 liters to millilitersExample #1: Convert 18 liters to milliliters

18 L18 L

18 liters = 18 000 milliliters18 liters = 18 000 milliliters

simply involves moving the decimal

ggmmLL 1010-1-1 1010-2-2 1010-3-3101011101022101033

BaseBaseunitunit

deci centi millidekahectokilo micro nano pico

1010-6-6 1010-9-91010-13-13

Example #2: Convert 450 milligrams to gramsExample #2: Convert 450 milligrams to grams

123

450 mg450 mg

0.450 g0.450 g

ggmmLL 1010-1-1 1010-2-2 1010-3-3101011101022101033

BaseBaseunitunit

deci centi millidekahectokilo micro nano pico

1010-6-6 1010-9-91010-13-13

Example #3: Convert 20 kilograms to milligramsExample #3: Convert 20 kilograms to milligrams

20 kg20 kg

1 2 3 4 5 6

20 kg = 20 000 000 mg20 kg = 20 000 000 mg

For more review see “The Ladder Method” http://www.nextvista.org/metric_conversions/

Chemistry Essential Skills

Beakers hold solids or liquids that will not release gases when reacted or are unlikely to splatter if stirred or heated.

Erlenmeyer flasks hold solids or liquids that may release gases during a reaction or that are likely to splatter if stirred or heated.

A test tube holder is useful A test tube holder is useful for holding a test tube which for holding a test tube which is too hot to handle.is too hot to handle.

A graduated cylinder is used A graduated cylinder is used to measure volumes of to measure volumes of liquids.liquids.

Rubber stoppers are used to close containers to avoid spillage or contamination.

Containers should never be heated when there is a stopper in place.

Spot plates are used when we want to perform many small scale reactions at one time. We will use these many times during the year.

A watch glass is used to hold a small amount of solid, such as the product of a reaction.

A medicine dropper is used to transfer a small volume of liquid (less than one mL).

On top of each medicine dropper is a “rubber bulb”

Weighing boats are used to weigh solids that will be transferred to another vessel.

Spatulas are used to dispense solid chemicals from their containers.

Chemicals should never be Chemicals should never be transferred with your bare hands.transferred with your bare hands.

Crucibles are used for heating certain solids, particularly metals, to very high temperatures.

Bunsen burners are used for the heating of nonvolatile liquids and solids.

The clay triangle is used as a support for porcelain crucibles when being heated over a Bunsen burner.

Chemistry Essential Skills

Uncertainty

Determine the smallest mark that can be read with certainty on your measurement instrument.

Read the measurement using all certain digits and one uncertain digit.

Certain digits are determined from the calibration marks on the instrument.

The uncertain digit (the last digit of the reading) is estimatedestimated and is “between” the lines.

Example: Measuring volume of a liquid in a graduated cylinder

Be careful to determine the correct markings (1degree vs. 2 degrees) between numbers on any instrument.Once again, record certain plus one estimated digit, even if it is a ZERO.

Determine the readings shown below on the Celsius thermometers:

_ _ . _ C _ _ . _ C8 7 3 5

Chemistry Essential Skills

Uncertainty and Significant Figures

Cartoon courtesy of Lab-initio.com

Scientific Notation