Chemistry - Ch 2 Flashcards

(76 cards)

0
Q

Law of constant composition

A

In a given compound, the relative numbers and kinds of atoms are constant

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1
Q

Atoms

A

Smallest particles of an element that retain the chemical identity of the element

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2
Q

Law of conservation of mass/matter

A

Total mass of materials present after a chemical reaction is the same as the total mass present b4 the reaction; basis for Postulate 3

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3
Q

Law of multiple proportions

A

If two elements A & B combine to form more than one compound, the masses of B can combine with a given mass of A are in the ratio of small whole numbers

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4
Q

Subatomic particles

A

Smaller parts of an atom

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5
Q

Cathode rays

A

Radiation originating from the negative electrode (cathode)

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6
Q

Coulomb

A

SI unit for electrical charge

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7
Q

Charge of a single electron

A

1.602 x 10^-19

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8
Q

Thomson’s charge to mass ratio

A

1.76 x 10^8 C/g

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9
Q

Mass of electron

A

9.10938 x 10^-28g; 2000 times smaller than hydrogen (lightest atom)

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10
Q

Radioactivity

A

Spontaneous emission of radiation; discovered by Henri Becquerel, who urged Marie Curie & her husband Pierre to isolate the radioactive components of uranium

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11
Q

3 types of radiation

A

Ernest Rutherford: alpha , beta, gamma (y); each type responds differently in an electric field - a & b are bent by it; y is unaffected

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12
Q

Beta rays

A

High speed electrons; = radioactive element of cathode rays; attracted to a positively charged plate

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13
Q

Alpha rays

A

Positive charge; attracted toward a negative plate

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14
Q

Gamma rays

A

High energy radiation similar to x-rays; does not consist of particles, carries no charge

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15
Q

Nucleus

A

Mass of atom & all of its positive charge reside in this very small dense region per Ernest Rutherford in his scattering experiment, which disproved JJ Thomson’s plum pudding model; protons & neutrons reside in nucleus

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16
Q

Discovery of protons (+ particles)

A

1919, Ernest Rutherford

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17
Q

Discovery of neutrons (neutral)

A

1932, James Chadwick

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18
Q

Proton charge (electronic charge)

A

+1.602 x 10^-19 C

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19
Q

Every atom has ___________ number of electrons & protons so atoms have no net electrical charge

A

Equal

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20
Q

1 Atomic mass unit (amu)

A

1.66054 x 10^-24g; protons & neutrons’ masses nearly equal, both much greater than an electron; proton’s mass: 1.0073 amu; neutron: 1.0087 amu; electron: 5.486 x 10^-4 amu; 1g= 6.02214 x 10^23amu

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21
Q

Angstrom

A

Non SI unit of length to express atomic dimensions

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22
Q

Atomic number

A

Number of protons in the nucleus of an atom

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23
Q

Mass number

A

Element symbol with subscript & superscript to left; superscript = mass # (protons + neutrons); subscript = atomic # (# of protons or electrons)

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24
Isotopes
Atoms with identical atomic numbers but different mass numbers(same # of protons, different # of neutrons)
25
Average atomic mass
Masses of its various isotopes & their relative abundances
26
Mass spectrometer
Most direct and accurate means for determining atomic & molecular weights
27
Mass spectrum
Graph of the intensity of the detector signal vs particle atomic mass
28
Periodic table
Most significant tool chemists use for organizing & remembering chemical facts; arrangement of elements in order of increasing atomic number, with elements having similar properties placed in vertical columns
29
Periods
Horizontal rows of periodic table
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Groups
Vertical columns of periodic table; AB designations with Arabic or Roman numerals, or IUPAC (Internat'l union of pure chemistry) 1-18 with no letters; similar properties b/c same arrangement of electrons @ periphery of their atoms
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Coinage metals
Copper (cu), silver (ag), & gold (au); pt of gp 1B
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Alkali metals (1A)
Li, Na, K, Rb, Cs, Fr
33
Alkaline earth metals (2A)
Be, Mg, Ca, Sr, Ba, Ra
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Chalcogens (6A)
O, S, Se, Te, Po
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Halogens (7A)
F, Cl, Br, I, At
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Noble/rare gases (8A)
He, Ne, Ar, Kr, Xe, Rn
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Metallic elements (metals)
All elements on left side and in middle of periodic table except hydrogen; share properties - luster, high electrical/heat conductivity; solid @ rm temp (except mercury)
38
Nonmetallic elements (nonmetals)
Separated from metals on table by diagonal steplike line from boron (B) to astatine (At); includes hydrogen; @ rm temp, some gaseous, some solid, 1 liquid; differ from metals in appearance & other physical properties
39
Metalloids
Elements that lie along line between metals & nonmetals that have properties that fall btwn both (ex.antimony-Sb)
40
Nuclear reactions
Reaction btwn uranium & neutrons that creates plutonium
41
Transuranium elements
Elements beyond uranium (92) on periodic table; not found in nature; can only be synthesized via nuclear reactions
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Molecule
Assembly of 2+ atoms tightly bound together
43
Chemical formula
Represents molecular form of an element
44
Diatomic molecule
Molecule made up of 2 atoms; hydrogen (H2), oxygen (O2), nitrogen (N2) & the halogens (F2, Cl2, Br2, I2) normally occur as diatomic molecules
45
Ozone
O3; sharp, pungent smell, toxic
46
Molecular compounds
Compounds composed of molecules (contain more than 1 type of atom)
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Molecular formulas
Chemical formulas that indicate actual numbers and types of atoms in a molecule
48
Empirical formulas
Chemical formulas that only give the relative number of atoms of each type of molecule; subscripts = smallest possible whole # ratios
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Structural formula
Shows which atoms are attached to which within the molecule; atoms represented by chemical symbols, lines represent bonds
50
Perspective drawing
Drawing a structural formula to show the angles at which atoms are joined together
51
Ball-and-stick model
Show atoms as spheres & bonds as sticks; accurately represents angles of attachment
52
Space-filling model
Depicts what the molecule would look like if the atoms were scaled up in size; angles hard to see
53
Ion
Charged particle formed by removing or adding electrons to a neutral atom; positively charged ion = cation; negatively charged ion = anion
54
Metal ions _______ electrons to form cations; nonmetals ________ electrons to form anions
Lose;gain
55
Polyatomic ions
Atoms joined as a molecule but with a net positive or negative charge (ex. NH4+, ammonium ion; or SO4 2-, sulfate ion)
56
Ionic compound
Compound with both positively & negatively charged ions; in general cations are metal ions & anions are nonmetal ions; ionic compounds are generally combos of metals & nonmetals ex. NaCl (molecular compounds generally = nonmetals only ex.H2O); only empirical formulas can be written for most ionic compounds
57
Chemical nomenclature
System used in naming substances (Latin nomen - name - & calare - to call)
58
Organic compounds
Carbon, usually in combo with hydrogen, oxygen, nitrogen, or sulfur; all other compounds are inorganic
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Monatomic ions
Ions formed from a single atom
60
Transition metals
Metals that can form more than one cation; occur in middle block of elements on periodic table, from group 3B to 2B; 1A (Na+, K+, & Rb+), 2A (Mg2+, Ca2+, Sr2+, Ba2+), 3A (Al3+) & 2 transition metal ions Ag+ (1B) & Zn2+ (2B) form only 1cation
61
Cations formed from nonmetal ions have names that end in _________
-ium ex. NH+4 (ammonium ion); H3O+ (hydronium ion); both ex are polyatomic; vast majority of cations are monatomic metal ions
62
Monatomic anions (neg ions) are formed by replacing ending with ______
IDE ex H- (hydride); O2- (oxide); N3- (nitride); a few simple polyatomic anions have names ending in IDE (OH- = hydroxide; CN- = cyanide; O2 2- = peroxide)
63
Oxyanions
Polyatomic anions containing oxygen; end in -ate (most common oxyanion of an element) or -ite (oxyanion that has same charge but 1 atom fewer (ex. NO3- = nitrate; NO2- = nitrite)
64
Anions derived by adding H+ to an oxyanion are named by adding as a prefix the word ____ or _____
Hydrogen or dihydrogen (ex. CO3 2- : carbonate ion; HCO3- : hydrogen carbonate; PO4 3- : phosphate ion; H2PO4 - : dihydrogen phosphate ion; each H+ reduces the negative charge of the parent ion by 1; older method for naming is to use prefix bi- (HCO3- = bicarbonate)
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Prefix hypo
One O atom fewer than oxyanion ending in ite ex. ClO2- = chlorite; ClO- = hypochlorite (one O atom fewer than chlorite)
66
Ionic compounds consist of the ____name followed by the ____ name
Cation; anion (ex. CaCl2 = calcium chloride)
67
Acid
substance whose molecules yield hydrogen (h+) ions when dissolved in water; composed of an anion connected to enough H+ ions to neutralize/balance the anion's charge
68
Acids containing anions whose names end in -ate or -ite or named by changing -ate to ___ and -ite to ___ then adding the word acid
-ic; -ous (Ex. ClO4 - : perchloric --> HClO4 (perchloric acid); ClO3 - : chlorate --> HClO3 (chloric acid); ClO2- : chlorite --> HClO2 (chlorous acid); ClO- : hypochlorite --> HClO (hypochlorous acid)
69
Names & Formulas of Binary Molecular Compounds - 3 Rules
(1) Name of element farther to left in table usually written 1st (exception = Oxygen; always last except when combined with fluorine (2) if both elements are in the same group, the one having the higher atomic # is named 1st (3) name of 2nd element is given an -ide ending (4) Greek prefixes are used to indicate # of atoms of each element; mono never used with 1st element; prefix ends in a or o & the name of 2nd begins with a vowel, a or o is often dropped
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Prefixes for Naming Binary Compounds (10)
Mono (1), Di (2), Tri (3), Tetra (4), Penta (5), Hexa (6), Hepta (7), Octa (8), Nona (9), Deca (10)
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Organic Chemistry
study of compounds of carbon
72
Hydrocarbons
Compounds that contain only carbon and hydrogen
73
Alkanes
each carbon atom is bonded to four other atoms (3 simplest = methane, CH4 =1 carbon; ethane, C2H6 = 2 carbons, & propane, C3H8 = 3 carbons); 4C = butane; 8 = octane (C8H18)
74
Functional groups
specific groups of atoms
75
Alcohol
Obtained by replacing an H atom of an alkane with an -OH group; replace -ane ending with -ol