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Flashcards in Powerpoint Exam 1 Deck (56):
1

chemistry

study of the composition properties and interactions of matters

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elements

building blocks (alphabets) of matters
- pure substances that cannot be separated into simpler substances by ordinary laboratory process

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example of elements

oxygen, hydrogen, carbon, gold

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building blocks of matter

1 oxygen + 2 hydrogen --> water
1 carbon + 2 oxygen --> carbon dioxide

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as of 2007 how many known elements are there and how many can be found in nature?

117 known elements
- 94 can be found in nature

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the elemental substance

- each element has it sown unique physical and chemical properties
- each has its own name
- some are named for their appearance, others for planets, mythological figures, scientists, or places

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symbols of elements

consists of 1 or 2 leters
- Capital and lower case

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particular nature of matters

- macroscopic
- submicroscopic
- macroscopic
- properties and interactions of submicroscopic particles of atoms and molecules determines the properties and behaviors of matter we experience and observe macrocopicly

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three terms for the submicroscopic particles

atoms
molecules
ions

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atom

smallest particle of an element that can exist and still have chemical properties of the element

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molecules

2 or more atoms joined together in a specific arrangement

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ions

atoms or a group of bonded atoms with an electrical charge

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all atoms of a given elements are?

identical
- the atoms of a given element are different from those of any other element

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what is the basic unit for chemical changes/chemical reactions?

atom

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molecular view of an element

one type of atoms in each elements

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molecules

- group of two or more atoms joined in a specific geometrical arrangement and behave like a single unit

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classify molecules by the number of atoms


- Diatomic molecule
- triatmic
- tetratomic

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classify molecule by the type of attoms

homoatomic molecules
heteroatomic molecules

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homoatomic

- molecules in which all atoms present are of the same kind
- pure substance containing homoatomic molecules must be an element

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heteroatomic molecules

- molecules in which two or more kinds of atoms are present
- a pure substance containing heteroatomic molecules must be compounds

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what is matter? and example

matter is anything which has mass and takes up space (volume)
ex: sand (solid)
- water (liquid)
- air (mixture of gases)
- human body (solid, liquid, gas)

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what kind science is chemistry?

empirical science
- based on the results of experiments/observations

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common types of measurements in chemistry

Length - m
Mass - g
Volume - L
Time - duration of experiment or observation

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certain digits

given by the smallest grid

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uncertain digit

by estimate

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precision of a measurement depends on the?

instruments

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the uncertain digits is always the?

right most digit

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significant figures

the digits in any measurement that are known with certainty plus 1 digit that is uncertain (estimate digit)

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sig fig - multiplication and division

answer should contain the same number of sig fig as the measurement with the least number of significant digits

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sig fig - +/-

answer many not have any more decimal places than the least accurate number

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exact numbers

counting
definition
unit conversion

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measure number

obtained by using instruments

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Density

- the ratio between mass and volume
D = M/V

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periodic table

- graphical display of elements
- elements are arranged by increasing atomic number
- elements with similar properties are placed in same column of the display

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periodic table: rows and column

- 7 rows: 7 periods
- 18 columns: 18 groups (8 group a and 10 group B)

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major groups in the period table

- alkali metals (1st column - except for helium)
- alkali earth metals (2nd column)
- transition metals (3-12th column)
- halogens (2nd to last column or 17th)
- noble gases ( last column)
- inner transition metals (the ones separated)

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alkali metals

- group 1A
- silver colored, soft, low density metals
- chemically highly reactive, rarely found in elemental form in nature
- reacts strongly with water to form base-alkali metal

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Alkali Earth Metals

- Group 2A
- harder, higher melting, and denser than alkali metals
- reactive, but less than corresponding alkali metal
- form stable, insoluble oxides from which they are normally extracted
- oxides are basic - alkaline earth

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Group 7A: Halogens

- chemically highly reactive
- found in nature only in compounds or as ions
- the elemental forms are made in laboratory
- each element exist as diatomic molecules
- only group exhibiting all 3 states at room temperature:
-- F2, Cl2 = gas
-- Br2 = liquid
-- I2 = Solids

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Group 8A Noble gas

- chemically very stable
- rarely react with other elements
- exist in nature as odorless, colorless monoatomic gases

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different parts of periodic table which are located at different parts

- metals
- non metals
- metalloids

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metals

- left side of zigzag
- except Helium (non metal)
- shiny, ductile, malleable
- good conductor
- high melting points
- high density

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metalloids

- zigzag border separating metals and non metals
- blue-gray, shiny
- brittle, easily shattered
- poor conductor
- medium melting points
- medium density

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nonmetals

- right of zigzag point
- dull
- brittle, easily shattered
- poor conductor
- lower melting points
- lower density

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physical state of elements
liquid

Mercury and Bromine

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proton

charge of +1
mass of 1 amu
in nucleus

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neutron

charge of 0 or neutral
mass of 1 amu
located in nucleus

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electron

electrical charge of -1
mass of .0005 amu
located in: dispersed through out electron cloud; not in nucleus

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amu

atomic mass unit

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atomic number of an element

Z
- ID # of the element
- number of the proton

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what is an element

pure substance in which all atoms present have the same atomic number

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Z

# of both p+ and e-

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isotopes

atoms of the same element with different numbers of neutrons (mass of an atom)
- same element with different mass
- same number of electrons
- same chemical properties

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mass number

symbol A
A = p+ + nº

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isotope symbol

A
E
Z
A= mass
E = atomic symbol
Z = electron

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weighted average mass

- the observed atomic mass for an element is the weighted average mass, based on the weight of each individual isotope