CH 101 Exam 1

Significant Figures

-all nonzero digits are significant (66.4)
-interior zeros are significant (4.0208)
-trailing zeros after the . (5.10)
-trailing zeros before the . (50.00)
-NOT:trailing zeros (50), leading zeros (0.0005)

Scientific notation

1847= 1.847x10^3

Metric Units and prefixes

length-meter
mass-kilogram
time-second
temperature-kelvin

Density

D=m/v

Accuracy & Precision

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Symbols and names of elements

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Matter

anything that occupies space and has mass

Matter's 3 physical states

solid-close together, definite shape & volume
liquid-definite volume
gas-far apart, compressible

Physical properties/changes

-one that a substance displays without changing its composition
-phase changes:boiling, melting, subliming, freezing, & condensing
-odor
-substance displays w/o changing its composition
-atomic or molecular composition doesn't change

Chemical Properties/Changes

-one that a substance displays only through changing its composition
-flammibility of a gas
-acidity, reactivity, combustibility
-bubbles, odors, burning or flames, insoluble precipitate, heat or light is given off

Pure Substances

-composed of only one type of atom or molecule
-elements:one type of an atom-He,O,I
-molecule
-compound:fixed amount of two or more elements-H20,sugar, salt

Mixture

composed of two or more different types of atoms or molecules combined in variable portions
-Homogeneous:composition is the same throughout (saltwater or sweet tea)
-Heterogeneous:composition varies (oil in water)

Molecular Compounds

-made of two nonmetals
-share electons
-prefixes
-use full name of first metal
-2nd element -ide
1-mono
2-di
3-tri
4-tetra
5-penta
6-hexa
7-hepta
8-octa
9-nona
10-deca

Celcius to Kelvin

1 degree celsius=274.15

Energy

-Kinetic: associated with its motion
-Potential: associated with its position or composition
-Heat= mass x specific heat x temp change

Specific Heat

-quantity of heat(energy) that changes the temp. of exactly 1 gram of a substance by 1 degree Celsius
-SH= amount of heat(cal or J)/1g x 1C

Law of conservation of Matter

in chemical reactions, the total mass of the products must equal the total mass of the reactants

Law of Conservation of Energy

energy can neither be created or destroyed

Atomic Theory

1-every element is composed of tiny indestructible particles called atoms
2-all atoms of a giben element have the same mass and other properties that distinguish them from atoms of other elements
3-atoms combine in simple, whole-number ratios to form compounds

Subatomic Particles

Protons
Neutrons
Electrons

Atomic number

-number of protons in the nucleus of an atom
-gives the identity of the element

Mass number

-number of protons and neutrons in the nucleus of an atom
-calculated as the weighted average of all isotopes of an element

Isotopes

-atoms w/ the same nunber of protons & different number of neutrons

Metals

-elements that tend to lose electrons in chemical reactions
-found at the left side and center

Nonmetals

-elements that tend to gain electrons in chemical reactions
-found at the upper right

Transition Metals

Mn-manganese
Fe-iron
Ni-nickel
Cu-copper
Zn-zinc
Ag-silver
Hg-mercury
W-tungsten
Au-gold

Alkali Metals

-Group 1
-+1 charge
Li-lithium
Na-sodium
K-potassium
Rb-rubidium
Cs-caesium
Fr-francium
H-hydrogen

Alkali-earth Metals

Group 1
2+
Be- beryllium
Mg-magnesium
Ca-calcium
Sr-strontium
Ba-barium
Ra-radium

Chalcogens

...

Halogens

Group 7- very reactive

Noble Gases

Group 8
Full shell
He-helium
Ne-neon
Ar-argon
Kr-krypton
Xe-xenon
Rn-radon

Ionic Compounds

-compound composed of a metal and nonmetal
-basic unit is the FORMULA UNIT
-Cations-metals tend to lose electrons from cations
-Anions-nonmetals tend to gain electrons from anions

Metalloids

Semimetals
-display mixed properties
B-
Si
Ge
As
Sb
Te
Po
At

Monatomic ions

...

Polyatomic Ions

ions that are themselves composed of a group of atoms with an overall charge
LIST

Constant composition

all samples of a given compound have the same proportions of their constituent elements

Mass Composition

Mass Percent= mass of x/mass of compound x 100%

Nomenclature

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Nonmetal Binary compounds

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Acids

-molecular compounds that form H+ and an anion when dissolved in H20
-Binary Acids-H+ cations and monatomic anion(nonmetal); -hydro(anion name)-ic acid
-Oxyacids-H+ cations and polyatomic anion
-ate to -ic acid
-ite to -ous acid
carbonic acid, nitrous acid