# Chemistry Study Guide

Safety, Matter, and Measurement

Lab Safety

Dress appropriately

Follow directions and act appropriately

Know where emergency equipment is

MSDS

Material Safety Data Sheets- contain safety information about chemicals Converting metric units

Kilo Hecto Deca Base Deci Centi Milli

1000 100 10 1 1/10 1/100 1/1000 Significant Figures

NOT Significant Digits

“Placeholders”- Zeros before the decimal point and after the number - Zeros after the decimal point and before the number Significant digits

All non-zero digits

“sandwiched” zeros

Zeros after decimal point and after number

Addition and Subtraction- round to the least # decimal places Multiplication and Division- round to the least # significant digits Accuracy and Precision

Precision- The specificity of the measurement (ie: 3.0000001 g) Accuracy- The actuality if the measurement (ie: TRUE weight it 5.6 g)

Atoms, Isotopes, and Atom Theories

Using atomic number and mass # to count protons, electrons, and neutrons Atomic number= # protons= # electrons

Mass number= protons+ neutrons (so: mass # - # protons= #neutrons) Isotopes- variation of neutrons in an element(top left corner of atomic symbol) H, H, H

Counting protons, electrons, and neutrons in IONS

Ion- # of electrons (top right # on atomic symbol)

H, H, H

Cation(metal)- lost/less electrons(+)

Anion (non-metal)- gained/more electrons(-)

Calculating Average Atomic Mass from isotope masses and percentages Average Atomic Mass=

(amu x .%)+ (amu x .%)= aam

Atomic Theories

Dalton

Thomson

Rutherford

Gold-Foil Experiment

Shot alpha particles at gold foil; the particles either went straight through, or bounced back at large angles

Atoms, Molecules, Formula Units, Mole, Mole Conversions, Percent Composition Identifying atoms, molecules, and formula units

Atoms

Molecules

Formula units

Understanding one mole of a...

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