Chem 20 - Final Review

acid

a compound that forms electricity conducting aqueous solutions that turns blue litmus red, neutralizes bases, and react with active metals to produce hydrogen gas

acid (Arrhenius definition)

a substance that reacts with water to produce hydronium ions

alkali metal

a soft, silver-coloured metal that reacts violently with water; group 1 elements

alkaline-earth metal

a light, reactive metal that forms an oxide coating when exposed to air; group 2 elements

ambient conditions

surrounding or room temperature

anecdotal evidence

evidence that is based upon personal experience or hearsay

anion

a negatively charged ion

anhydrous

the form of a substance without any water of hydration

aqueous solution

a homogenous mixture of one or more solutes dissolved in water

polyatomic ions

a group of atoms with a net positive or negative charge on the whole group

hydrates

a pure substance that decomposes at a relatively low temperature to produce water and another substance; a substance containing loosely bonded water molecules

diatomic molecules

a molecule containing two atoms

molecule

an entity consisting of a group of non-metal atoms held together by covalent bonds

physical change

any change in the form of a substance in which the chemical composition does not change

chemical change

a change in which one or more new substances with different properties are formed as evidenced by changes in colour, energy, odour, or state

nuclear change

a change within the nucleus of a atom/ion that creates one or more new atoms/ions

kinetic molecular theory

the idea that the smallest entities of a substance are in continuous motion, colliding with each other and objects in their path

Avogadro's number

the characteristic number of protons in the nucleus of an atom of a particular element

valence electrons

an electron in the highest energy level of the atom; an electron available for a covalent bond or electron change

precipitate

a solid substance formed during a reaction in solution

bonding electron

a single unpaired electron, in a valence orbital, that can be shared or exchanged with another atom

electronegativity

a number that describes the relative ability of an atom to attract a pair of bonding electrons in its valence level

covalent bond

the simultaneous attraction of two nuclei for a shared pair of bonding electrons

ionic bond

the simultaneous attraction among positive and negative ions

VSEPR theory

a theory predicting and explaining the shape of a molecule based on the electrical repulsion of bonded and unbonded electron pairs in a molecule

polar molecule

a molecule in which the negative is not distributed symmetrically among the atoms, resulting in partial positive and negative charges on opposite ends of the molecule

intermolecular forces

the relatively weak forces of attraction and repulsion between molecules

intramolecular forces

the relatively strong bonds or forces of attraction and repulsion within a molecule; typically covalent bonds

van der Waals forces

weak attractive forces that molecules exert on each other, including London and dipole-dipole forces

titration

a technological process of carefully adding a solution from a burette into a measured, fixed volume of another solution until the reaction is judged to be complete

hydrogen bonding

the simultaneous attraction of a hydrogen nucleus, that is covalently bonded to a very electronegative atom, for a lone pair of electrons on an adjacent molecule

crystal lattice

a continuous, three-dimensional pattern of atoms, ions, or molecules in a crystalline solid

atmospheric pressure

the force per unit area exerted by air on all objects

Boyle's Law

as pressure on a gas increases, the volume of the gas decreases proportionally provided that the temperature and amount of gas remain constant

Charle's Law

as the absolute temperature of a gas increases, the volume increases proportionally, provided that the pressure and amount of gas remain constant

combined gas law

the product of the pressure and volume of a gas sample is proportional to its absolute temperature in Kelvin

Law of Combining Volumes

when measured at the same temperature and pressure, volumes of gaseous reactants and products of chemical reactions are always in simple ratios of whole numbers

molar volume

the volume occupied by one mole of a gas at a specified temperature and pressure in units of litres per mole

electrolyte

a substance that conducts electricity in aqueous solution; also a liquid such as a molten solid that conducts electricity

nonelectrolyte

compounds that do not conduct electricity in aqueous solution nor in the molten/liquid state

dissociation

a separation and dispersal of previously bonded entities; the separation of ions that occurs when an ionic compound dissolves in water

ionization

a process by which a neutral atom or molecule is converted to an ion; the reaction of substances in water to create ions

standard solution

a solution with a concentration that is known with considerable certainty

stock solution

an initial, usually concentrated, solution from which samples are taken for dilution

hydronium ion

a hydrated hydrogen ion (H30+); the entity responsible for acidic properties in aqueous solutions

pH

a measure of the acidity of a solution as the negative exponent to the base of ten of the hydronium ion concentration; pH = -log(H30+)

pOH

a measure of the basicity of a solution as the negative exponent to the base of ten of the hydroxide ion concentration; pOH = -log(OH-)

strong acid/base

acid: a substance that forms a solution with strong acidic properties, such as low pH; a substance that reacts completely (>99%) with water to form hydronium ions

base: an ionic hydroxide that dissociates completely (>99%) to release hydroxide ions

weak acid/base

acid: a substance that reacts incompletely (<50%) with water to form few hydronium ions

base: an ionic or molecular substance that reacts partially (<50%) with water to produce relatively few hydroxide ions

monoprotic acid/base

acid: an acid that possess only one ionizable proton, HA, and can react only once with water to produce hydronium ions

base: a base that can react with water only once to produce hydroxide ions

polyprotic acid/base

acid: an acid with more than one acidic hydrogen available to react with water to form hydronium ions; an acid that can donate more than one proton

base: a base that can react more than once with water to form hydroxide ions; a base that can accept more than one proton

limiting reagent

the reactant that is completely consumed in a reaction

excess reagent

the reactant that is still present after a reaction has gone to completion

percent yield

actual yield/predicted or theoretical yield

what are the 6 VSEPR diagram shapes?

- linear (linear)

- trigonal planar

- tetrahedral

- trigonal planar (tetrahedral)

- angular

- linear (tetrahedral)

SATP conditions

25 degrees at 100kPa

STP conditions

0 degrees at 101.325kPa

what are the characteristics of molecular compounds?

solid, liquid, gases at SATP, low melting point, not conductive

what are the characteristics of ionic compounds?

crystalline at solid at SATP, high melting point, conductor

multi-valent metal

the ability of an atom to form a variety of ions

bonding capacity

the maximum number of single covalent bonds that an atom can form; determined by the number of bonding electrons in the atom

bond energy

the energy required to break a chemical bond; also the energy released when a bond is formed

what types of molecules form hydrogen bonds?

strong dipole-dipole forces with F-H, O-H, and N-H bonds

qualitative analysis

the identification of a specific chemical substance

quantitative analysis

the determination of the quantity of a substance present

dilution

the process of adding solvent to a solution to reduce its concentration

what factors can change the solubility of a substance

temperature and pressure

miscible liquid

a term used to describe liquids that dissolve completely in each other in any proportion

immiscible liquid

a liquid that doesn't dissolve completely in each other

what is the pH calculations?

* -log (H3O+) = pH

* 10pH = (H3O+)

what are the pOH calculations?

* -log (OH) = pOH

* 10pOH = (OH)

what are 4 similar physical properties all gases share?

- always fill their containers

- compressible

- diffuses

- temperature affects volume/pressure

what is Boyle's law calculation?

p1v1 = p2v2

what is Charle's law calculation?

v1/t1 = v2t2

what is the combined gas law calculation?

p1v1/t1 = p2v2/t2

what is the ideal gas law calculation?

pv = nRT

who created the periodic table?

Dmitri Mendeleev

halogens

a reactive nonmetal from group 17

noble gases

a very unreactive gaseous element from group 18

empirical definition

a statement that defines an object or a process in terms of observable properties

theoretical definition

a general statement that characterizes the nature of a substance or a process in terms of non-observables

what is the basic SI unit for chemical amount?

mole

ideal gas

a gas that obeys all the gas laws perfectly under all conditions; a hypothetical gas with molecules of negligible size and no intermolecular forces between the molecules

exothermic reaction

a chemical reaction that releases energy to the surroundings

endothermic reaction

a chemical reaction that absorbs energy from the surroundings

examples of dissociation equation

* NaCl --> Na+ + Cl