Quiz Bowl Chemistry

Front 1

Allotropes

Back 1

different structural modifications of an element; the atoms of the element are bonded together in a different manner.

Hint 1

graphite & diamond

Front 2

Law of Definite Proportions

Back 2

states that a chemical compound always contains exactly the same proportion of elements by mass.

Hint 2

sometimes called Proust's Law; fundamental law of stoichiometry

Front 3

Law of Multiple Proportions

Back 3

states that if two elements form more than one compound between them, then the ratios of the masses of the second element which combine with a fixed mass of the first element will be ratios of small whole numbers

Hint 3

sometimes called Dalton's Law; fundamental law of stoichiometry

Front 4

Law of Conservation of Mass

Back 4

states that the mass of an isolated/closed system will remain constant over time.

Hint 4

principle is equivalent to the conservation of energy; fundamental law of stoichiometry

Front 5

Stoichiometry

Back 5

a branch of chemistry that deals with the relative quantities of reactants and products in chemical reactions.

Front 6

Reaction Stoichiometry

Back 6

describes the quantitative relationships among substances as they participate in chemical reactions.
In the hint, this describes the 1:3:2 ratio of molecules of nitrogen, hydrogen, and ammonia.

Hint 6

N2 + 3H2 → 2NH3

Front 7

Composition Stoichiometry

Back 7

describes the quantitative (mass) relationships among elements in compounds.
In the hint, this describes the nitrogen to hydrogen ratio in the compound ammonia: 1 mol of ammonia consists of 1 mol of nitrogen and 3 mol of hydrogen. As the nitrogen atom is about 14 times heavier than the hydrogen atom, the mass ratio is 14:3, thus 17 kg of ammonia contains 14 kg of nitrogen and 3 kg of hydrogen.

Hint 7

N2 + 3H2 → 2NH3

Front 8

Gas Stoichiometry

Back 8

deals with reactions involving gases, where the gases are at a known temperature, pressure, and volume, and can be assumed to be ideal gases. For gases, the volume ratio is ideally the same by the ideal gas law, but the mass ratio of a single reaction has to be calculated from the molecular masses of the reactants and products. In practice, due to the existence of isotopes, molar masses are used instead when calculating the mass ratio.

Hint 8

N2 + 3H2 --> 2NH3

Front 9

Limiting Reactant

Back 9

The reactant that is used up completely in the reaction

Front 10

Solution

Back 10

The solute dissolved in the solvent

Front 11

Titration

Back 11

a common laboratory method of quantitative chemical analysis that is used to determine the unknown concentration of an identified analyte

Hint 11

Also known as volumetric analysis

Front 12

Equivalence Point

Back 12

in a chemical reaction, the point at which an added titrant is stoichiometrically equal to the number of moles of substance (known as analyte) present in the sample: the smallest amount of titrant that is sufficient to fully neutralize or react with the analyte.

Hint 12

coincides with an endpoint, an indicator color will cahnge

Front 13

Solvent

Back 13

a substance that dissolves a solute

Hint 13

more concentrated than solute; water is the universal solvent

Front 14

Solute

Back 14

a substance dissolved in a solvent

Hint 14

less concentrated than the solvent

Front 15

Periodic Law

Back 15

in chemistry, law stating that many of the physical and chemical properties of the elements tend to recur in a systematic manner with increasing atomic number.

Hint 15

The chemical law that the properties of all the elements are periodic functions of their atomic weights was developed independently by two chemists: in 1869 by Dmitry Mendeleyev, a Russian, and in 1870 by Julius Lothar Meyer, of Germany. The key to the success of their efforts was the realization that previous attempts had failed because a number of elements were as yet undiscovered and that vacant places must be left for such elements in the classification.

Front 16

Metals

Back 16

high conductivity, high thermal conductivity, malleable, few electrons in outer shell, metallic character increases as you go down and left on periodic table

Hint 16

all but mercury are solid(Ce and Ga melt), gray except AG and AU

Front 17

Electrolytes

Back 17

substances whose aqueous solutions conduct electricity well, includes strong acids, strong soluble bases, most soluble salts

Front 18

Precipitates

Back 18

the formation of a solid in a solution or inside another solid during a chemical reaction or by diffusion in a solid.

Front 19

Oxidation number

Back 19

the charge that it would have if all the ligands were removed along with the electron pairs that were shared with the central atom.

Hint 19

The oxidation number of an element in its elementary form is zero. For example, hydrogen, oxygen, nitrogen, chlorine, phosphorus, sulphur, copper, iron etc. have oxidation number equal to zero.
The sum of the oxidation numbers of all the atoms in an ion or molecule is its net charge.
In compounds with non-metals, the oxidation number of hydrogen is +1. However, when hydrogen is compounded with a metal, its oxidation number reduces to −1 (the metal being a more electropositive element).
Oxygen has been assigned oxidation number of −2 in its compounds. However, there are certain exceptions also. In peroxides such as hydrogen peroxide, the oxidation number of oxygen is −1. In oxygen difluoride the oxidation number of oxygen is +2 while in dioxygen difluoride, oxygen is assigned an oxidation number +1 (fluorine being a more electronegative element).
The atom with higher electronegativity, typically a nonmetallic element, is assigned negative oxidation number while the other atom, often a metallic element, is given positive oxidation number.

Front 20

Oxidation

Back 20

loss of electrons

Front 21

Reduction

Back 21

gain of electrons

Front 22

Oxoacids

Back 22

an acid that has the elements hydrogen and oxygen along with another element, often a nonmetal. Equivalently, they contain hydrogen in addition to a polyatomic ion.

Hint 22

also called a ternary acid

Front 23

Ligand

Back 23

an ion or molecule (functional group) that binds to a central metal atom to form a coordination complex

Front 24

Photoelectric effect

Back 24

x

Front 25

Heisenberg Uncertainty Principle

Back 25

You cannot know both momentum & position of an electron

Front 26

Aufbau Principle

Back 26

x

Front 27

Pauli Exclusion Principle

Back 27

x

Front 28

Hund's Rule

Back 28

x

Front 29

Paramagnetic

Back 29

x

Front 30

Diamagnetic

Back 30

x

Front 31

Ferromagnetic

Back 31

x

Front 32

Combustion reaction

Back 32

oxygen combines rapidly, very exothermic, hydrocarbon+oxygen yields carbon dioxide, water and heat

Front 33

Roasting

Back 33

extracting free metals by heating an ore in air(oxygen)

Front 34

Ionic compounds

Back 34

high melting point, soluble in polar solvents, insoluble in nonpolars, molten and aqueous solutions conduct electricity; large electronegativity difference between atoms

Front 35

Lewis dot formulas

Back 35

show valence electrons

Front 36

Octet Rule

Back 36

most compounds achieve noble gas configurations

Front 37

Resonance

Back 37

two or more Lewis structures describe bonding

Front 38

Formal Charge

Back 38

charge on atom in a molecule or polyatomic ion

Front 39

Polar covalent bond

Back 39

electrons shared unequally; creates dipole

Front 40

Sigma bond

Back 40

x

Front 41

Pi bond

Back 41

x

Front 42

dipole

Back 42

x

Front 43

molecular orbital

Back 43

an orbital resulting from overlap and mixing of atomic orbitals of different atoms; belongs to a molecule as a whole

Front 44

Antibonding orbital

Back 44

molecular orbital higher in energy than any of atomic orbitals from which it is derived; lends stability when populated; marked with an asterisk