question

mass

answer

a measurable amount of matter an object contains

question

volume

answer

measurable amount of space occupied by an object

question

extensive property

answer

a property that depends on the amount of matter in a sample (ex. mass and volume)

question

intensive property

answer

a property that depends on the type of matter in the sample, not the amount of matter (ex. hardness)

question

substance

answer

matter that has a uniform and definite composition

question

physical property

answer

a quality or condition of a substance that can be observed or measured without changing the substance's composition

question

solid

answer

a form of matter that has a definite shape and volume and is not easily compressed

question

liquid

answer

a form of matter that has an indefinite shape, flows, and has a fixed volume and is not easily compressed

question

gas

answer

a form of matter that takes the shape and volume of its container and is easily compressed

question

vapor

answer

the gaseous state of a substance that is generally a liquid or solid at room temperature

question

physical change

answer

a change where some properties of a material change, but the composition of the material does not change

question

mixture

answer

a physical blend of two or more components

question

heterogeneous mixture

answer

a mixture in which the composition is not uniform throughout; contains two or more phases

question

homogeneous mixture

answer

a mixture in which the composition is uniform throughout; contains one phase

question

solution

answer

another name for a homogeneous mixture; usually a liquid

question

phase

answer

describes any part of a sample with uniform composition and properties

question

filtration

answer

the process that separates a solid from the liquid in a heterogeneous mixture

question

distillation

answer

a separation of mixtures were a liquid is boiled to produce a vapor that is condensed into a liquid

question

element

answer

the simplest form of matter that has a unique set of properties

question

compound

answer

a substance that contains two ore more elements chemically combined in a fixed proportion

question

chemical change

answer

a change that produces matter with a different composition than the original matter

question

chemical symbol

answer

one or two letters that represent a specific element

question

chemical property

answer

the ability of a substance to undergo a specific chemical change

question

chemical reaction

answer

one or more substances changing into one or more new substances

question

reactant

answer

a substance present at the start of a reaction

question

product

answer

a substance produced in the reaction

question

precipitate

answer

a solid that forms and styles out of a liquid mixture

question

Law of Conservation of Mass

answer

mass is neither created nor destroyed

question

measurement

answer

a quantity that has both a number and a unit

question

scientific notation

answer

a given number written as the product of two numbers: a coefficient (between 0 and 10) and 10 raised to a power

question

accuracy

answer

a measure of how close a measurement comes to the actual of true value of whatever is measured

question

precision

answer

a measure of how close a series of measurements are to one another

question

accepted value

answer

the correct value base on reliable references

question

experimental value

answer

the value measured in the lab

question

error

answer

the difference between the experimental value and the accepted value

question

percent error

answer

the absolute value of the error divided by the accepted value, multiplied by 100%

question

significant figures

answer

all of the digits that are known plus a digit that is estimated. • Every nonzero digit in a reported measurement is significant • Zeros appearing between non-zeros are significant • Leftmost zeros appearing in front of nonzero digits are NOT significant • Zeros at the end of a number and to the right of a decimal point are significant • Zeros at the rightmost end of a measurement that are to the left of a decimal point are NOT significant • When multiplying or dividing, you round the answer to the same number of significant figures as the measurement with the least number of significant figures • When adding or subtracting, you round the answer to the same number of decimal places as the measurement with the least number of decimal places

question

SI (The International System of Units)

answer

meter (m) used for length, kilogram (kg) used for mass, kelvin (K) used for temperature, second (s) used for time, mole (mol) used for the amount of a substance) (and the less commonly used candela (cd) used for luminous intensity and ampere (A) used for electric currents)

question

density

answer

the ratio of the mass of an object to its volume. generally decreases as temperature increases

question

atomic number

answer

the number of protons in the nucleus of an atom of that element

question

mass number

answer

the total number of protons and neutrons in an atom

question

isotopes

answer

atoms that have the same number of protons but different numbers of neutrons

question

atomic mass unit (amu)

answer

1/12 of the mass of a carbon-12 atom. the mass of a single proton or a single neutron is 1 amu

question

atomic mass

answer

a weighted average mass of the atoms in a naturally occurring sample of the element

question

periodic table

answer

an arrangement of elements in which the elements are separated into groups based on a set of repeating properties

question

period

answer

each horizontal row of the periodic table

question

group

answer

also known as a family, each vertical column of the periodic table

question

electron configuration

answer

the ways in which electrons are arranged in various orbitals around the nuclei or atoms

question

aufbau principle

answer

electrons occupy the orbitals of lowest energy first

question

Pauli exclusion principle

answer

an orbital can hold at most two electrons, which are in opposite directions with opposite spins

question

Hund's rule

answer

one electron per orbital until all orbitals have one, then a second electron can fill each orbital

question

alkali metals

answer

elements in group 1A

question

alkaline earth metals

answer

elements in group 2A

question

halogens

answer

elements in group 7A

question

noble gases

answer

elements in group 8A

question

transition metals

answer

elements in groups 1B-8B in the main body of the periodic table. have electrons in d orbitals

question

metalloids

answer

some properties of metals, some properties of nonmetals. found along the staircase in the periodic table

question

inner transition metal

answer

appearing below the periodic table. have electrons in f orbitals

question

atomic radius

answer

one half of the distance between the nuclei of two atoms of the same element when the atoms are joined. In general, atomic size increases from top to bottom within a group and decreases from left to right across a period

question

ion

answer

an atom or group of atoms that has a positive or negative charge. Positive and negative ions form when electrons are transferred between atoms

question

cation

answer

an ion with a positive charge. Always smaller than the atoms from which they form.

question

anion

answer

an ion with a negative charge. Always larger than the atoms from which they form.

question

ionization energy

answer

the energy required to remove an electron from an atom. First ionization energy tends to decrease from top to bottom within a group and increase from left to right across a period

question

electronegativity

answer

the ability of an atom of an element to attract electrons when the atom is in a compound. Electronegativity values decrease from top to bottom within a group. For representative elements, the values tend to increase from left to right across a period.

question

valence electrons

answer

the electrons in the highest occupied energy level of an element's atoms. To find the number of valence electrons in an atom of a representative element, simply look at its group number.

question

electron dot structures

answer

diagrams that show valence electrons as dots

question

octet rule

answer

In forming compounds, atoms tend to achieve the electron configuration of a noble gas. An octet is a set of eight. Atoms of the metallic elements tend to lose their valence electrons, while atoms of some nonmetallic elements tend to gain electrons or share electrons with another nonmetallic element. An atom's loss of valence electrons produces a cation. The gain of negatively charged electrons by a neutral atom produces an anion

question

halide ions

answer

the ions that are produced when atoms of chlorine and other halogens gain electrons. All halogen atoms have seven valence electrons and need to gain only one electron to achieve the electron configuration of a noble gas. All halide ions have a charge of 1-

question

ionic compounds

answer

compounds composed of cations and anions, usually metal cations and nonmetal anions. They are electrically neutral. Most are crystalline solids at room temperature. Most have high melting points. Conducts electricity when aqueous or melted. Brittle when stressed enough. All are electrolytes

question

ionic bonds

answer

the electrostatic forces that hold ions together in ionic compounds

question

chemical formula

answer

shows the kinds and numbers of atoms in the smallest representative unit of a substance

question

formula unit

answer

the lowest whole-number ratio of ions in an ionic compound

question

coordination number

answer

the number of ions of opposite charge that surround the ion in a crystal

question

metallic bonds

answer

the attraction of the free-floating valance electrons for positively charged metal ions. The valence electrons of metal atoms can be modeled as a sea of electrons. They are arranged in an organized, crystalline structure. They conduct electricity as a solid, have high melting points, are hard, are malleable (can be bent) and ductile (can be stretched into a thin wire)

question

alloys

answer

mixtures composed of two or more elements, at least one of which is a metal. Their properties are often superior to those of their component elements.

question

covalent bond

answer

the atoms held together by sharing electrons. Electron sharing usually occurs so that atoms attain the electron configurations of noble gases

question

molecule

answer

a neutral group of atoms joined together by covalent bonds

question

diatomic molecule

answer

a molecule consisting of two atoms

question

molecular compound

answer

a compound composed of molecules. They have lower melting points and lower boiling points than ionic compounds

question

molecular formula

answer

the chemical formula of a molecular formula showing how many atoms of each element a molecule contains

question

single covalent bond

answer

the bond joining two atoms held together by sharing a pair of electrons

question

structural formula

answer

represents the covalent bonds by dashes and shows the arrangement of covalently bonded atoms

question

unshared pair

answer

a pair of valence electrons that is not shared between atoms, also called lone pair or nonbonding pair

question

double covalent bond

answer

a bond that involves two shared pairs of electrons

question

triple covalent bond

answer

a bond formed by sharing three pairs of electrons

question

coordinate covalent bond

answer

a covalent bond in which one atom contributes both bonding electrons

question

polyatomic ion

answer

a tightly bound group of atoms that has a positive or negative charge and behaves as a unit such as the ammonium ion

question

bond dissociation energy

answer

the energy required to break the bond between two covalently bonded atoms. The larger the bond dissociation energy, the stronger the covalent bond

question

resonance structure

answer

a structure that occurs when it is possible to draw two ore more valid electron dot structures that have the same number of electron pairs for a molecule or an ion

question

molecular orbitals

answer

orbitals that apply to the entire molecule

question

bonding orbital

answer

a molecular orbital that can be occupied by two electrons of a covalent bond

question

sigma bond

answer

when two atomic orbitals combine to form a molecular orbital that is symmetrical around the axis connecting two atomic nuclei

question

pi bond

answer

when a pi molecular orbital is filled with two electrons

question

tetrahedral angle

answer

109.5 degrees. four bonds surrounding the central atom

question

VSEPR theory

answer

valence-shell electron-pair repulsion theory that states that the repulsion between electron pairs causes molecular shapes to adjust so that the valence-electron pairs stay as far apart as possible

question

hybridization

answer

several atomic orbitals mix to form the same total number of equivalent hybrid orbitals. Orbital hybridization provides information about both molecular bonding and molecular shape

question

non-polar covalent bond

answer

when the atoms in the bond pull equally (as occurs when identical atoms are bonded) and the bonding electrons shared equally. Non-polar compounds have low melting points, dissolve in a non-polar solvent, do not conduct electricity, are symmetrical, and have dispersion intermolecular forces

question

polar covalent bond (polar bond)

answer

a covalent bond between atoms in which the electrons are shared unequally. The more electronegative atom attracts electrons more strongly and gains a slightly negative charge. The less electronegative atom has a slightly positive charge

question

polar molecule

answer

one end of the molecule is slightly negative and the other is slightly positive. It is a dipolar molecule and has dipole-dipole bonding or hydrogen bonding. It does not have a symmetrical structure, has a medium melting point, does not conduct electricity, is not flexible, and dissolves in a polar solvent.

question

dipole

answer

a molecule that has two poles

question

dipole interactions

answer

occurs when polar molecules are attracted to one another and are much weaker than ionic or covalent bonds

question

dispersion forces

answer

the weakest of all molecular interactions occurring between non-polar molecules

question

Hydrogen bonds

answer

attractive forces in which a hydrogen covalently bonded to a very electronegative atom is also weakly bonded to an unshared or lone electron pair of another electronegative atom

question

network solids

answer

solids in which all of the atoms are covalently bonded to each other, also called network crystals. Does not conduct, does not dissolve, extremely high melting point, strongest substance/compound (atoms are interlocked), does not break apart without the breaking of bonds, does not react with anything

question

surface tension

answer

the inward force, or pull, that tends to minimize the surface area of a liquid

question

surfactant

answer

any substance that interferes with the hydrogen bonding between water molecules and thereby reduces surface tension

question

aqueous solution

answer

water that contains dissolved substances

question

solvent

answer

dissolving medium

question

solute

answer

the dissolved particles

question

solvation

answer

the process by which the positive and negative ions of an ionic solid become surrounded by solvent molecules

question

electrolyte

answer

a compound that conducts an electric current when it is in an aqueous solution or in the molten state

question

non-electrolyte

answer

a compound that does not conduct an electric current in either aqueous solutions or the molten states

question

strong electrolyte

answer

a solution in which a large portion of the solute exists as ions

question

weak electrolyte

answer

conducts electricity poorly because only a fraction of the solute in the solution exists as ions

question

hydrate

answer

a compound that contains water of hydration

question

percent H2O

answer

(mass of water divided by mass of hydrate) multiplied by 100%

question

factors in determining the speed of dissolving

answer

increase in agitation (stirring), increase in temperature, increase in concentration, decrease in surface area

question

saturated solution

answer

contains the maximum amount of solute for a given quantity of a solvent at a constant temperature and pressure

question

solubility

answer

the amount of solute that dissolves in a given quantity of a solvent at a specified temperature and pressure often expressed in grams of solute per 100g of solvent

question

unsaturated solution

answer

a solution that contains less solute than a saturated solution at a given temperature and pressure

question

miscible

answer

describes two liquids that dissolve each other in all proportions

question

immicible

answer

liquids that are insoluble in one another

question

supersaturated solution

answer

contains more solute than it can theoretically hold at a given temperature

question

Henry's Law

answer

at a given temperature, the solubility of a fas in a liquid is directly proportional to the pressure of the gas above the liquid. As the pressure of the gas increases, the solubility of the gas decreases [(S1/P1) = (S2/P2)]

question

concentration

answer

a measure of the amount of solute that is dissolved in a given quantity of solvent

question

dilute solution

answer

a solution that contains a small amount of solute

question

concentrated solution

answer

a solution that contains a large amount of solute

question

Molarity (M)

answer

the number of moles of a solute divided by the liters of solution

question

Dilution Calculation

answer

M1 x V1 = M2 x V2 Diluting a solution reduces the number of moles of solute per unit volume, but the total number of moles of solute in solution does not change

question

Concentration in Percent by Volume (% v/v)

answer

(volume of solute/volume of solution) multiplied by 100%

question

Concentration in Percent by Mass (% m/m)

answer

(mass of solute/mass of solution) multiplied by 100%

question

colligative property

answer

a property that depends only upon the number of solute particles and not upon their identity. Three important colligative properties of solutions are vapor-pressure lowering, boiling-point elevation, and freezing-point depression

question

vapor-pressure lowering

answer

the decrease in a solution's vapor pressure is proportional to the number of particles the solute makes in solution

question

freezing-point depression

answer

the difference in temperature between the freezing point of a solution and the freezing point of the pure solvent. The magnitude of the freezing-point depression is proportional to the number of solute particles dissolved in the solvent and does not depend upon their identity

question

boiling-point elevation

answer

the difference in temperature between the boiling point of a solution and the boiling point of pure solvent. The magnitude of the boiling-point elevation is proportional to the number of solute particles dissolved in the solvent

question

molality (m)

answer

the number of moles of solute dissolved in one kilogram (1000 grams) of solvent

question

mole fraction

answer

the ratio of moles of that solute to the total number of moles of solvent and solute

question

thermochemistry

answer

the study of energy changes that occur during chemical reactions and changes in state

question

chemical potential energy

answer

the energy stored in chemical bonds of a substance

question

heat (q)

answer

the energy that transfers from one object to another because of a temperature difference between them. Always flows from a warmer object to a cooler object. q=mC ∆T

question

system

answer

the part of the universe on which you focus your attention

question

surroundings

answer

everything else in the universe besides the system

question

law of conservation of energy

answer

energy is neither created nor destroyed. if the energy of the system decreases during a chemical or physical process, the energy of the surroundings must increase by the same amount so that the total energy in the universe remains unchanged

question

endothermic process

answer

absorbs heat from the surroundings; the system gains heat as the surroundings cool down. Has a positive heat (q) value

question

exothermic process

answer

releases heat to its surroundings; the system loses heat as the surroundings heat up. Has a negative heat (q) value

question

heat capacity

answer

the amount of heat needed to increase the temperature of an object by exactly one degree celsius. Depends on the mass and chemical composition of the substance

question

specific heat

answer

the specific heat capacity is the amount of heat it takes to raise the temperature of one gram of the substance one degree celsius.

question

calorimetry

answer

The precise measurement of heat flow into or out of a system for chemical and physical processes. In calorimetry, the heat released by the system is equal to the heat absorbed by its surroundings. Conversely, the heat absorbed by a system is equal to the heat released by its surroundings.

question

calorimeter

answer

The insulated device used to measure the absorption or release of heat in chemical or physical processes

question

enthalpy (H)

answer

The heat content of a system at constant pressure equal to q. (q=∆H) Can be written as either a reactant or product

question

thermochemical equation

answer

A chemical equation that includes the enthalpy change

question

heat of reaction

answer

The enthalpy change for the chemical equation exactly as it is written usually reported as ∆ H which is equal to the heat flow at constant pressure

question

heat of combustion

answer

The heat of reaction for the complete burning of one mole of a substance

question

molar heat of fusion (∆Hfus)

answer

The heat absorbed by one mole of a solid substance as it melts to a liquid at constant temperature. The quantity of heat absorbed by a melting solid is exactly the same as a quantity of heat released when the liquid solidifies (∆Hfus=-∆Hsolid)

question

molar heat of solidification (∆Hsolid)

answer

The heat lost when one mole of a liquid solid solidifies constant temperature. The quantity of heat absorbed by a melting solid is exactly the same as a quantity of heat released when the liquid solidifies (∆Hfus=-∆Hsolid)

question

molar heat of vaporization (∆Hvap)

answer

The amount of heat necessary to vaporize one mole of a given liquid. The quantity of heat absorbed by vaporizing liquid is exactly the same as a quantity of heat released when the vapor condenses (∆Hvap=-∆Hcond)

question

molar heat of condensation (∆Hcond)

answer

The amount of heat released when one mole of vapor condenses at the normal boiling point. The quantity of heat absorbed by vaporizing liquid is exactly the same as a quantity of heat released when the vapor condenses (∆Hvap=-∆Hcond)

question

molar heat of solution (∆Hsoln)

answer

Enthalpy change caused by dissolution of one mole of substance

question

rate

answer

A measure of the speed of any change that occurs within an interval of time. The rate of chemical change for the reaction rate is usually expressed as the amount of reactant changing per unit time

question

Collision theory

answer

Atoms, ions, and molecules can react to form products when they collide with one another, provided that the colliding particles have enough kinetic energy.

question

Activation energy

answer

The minimum energy that colliding particles must have in order to react

question

Activated complex

answer

An unstable arrangement of atoms that forms momentarily at the peak of the activation-energy barrier

question

Transition state

answer

Another name for the activated complex

question

Factors affecting reaction rates

answer

The rate of a chemical reaction depends on temperature, concentration, particle size, and the use of a catalyst. Increasing temperature increases the rate, increasing concentration increases the rate, decreasing particle size increases the rate, and the use of a catalyst increases the rate.

question

Inhibitor

answer

A substance that interferes with the action of a catalyst

question

Reversible reaction

answer

A reaction in which the conversion of reactants to products and the conversion of products to reactants occur simultaneously

question

Chemical equilibrium

answer

When the rates of the forward and reverse reactions are equal, the reaction has reached a state of balance. At chemical equilibrium, no net change occurs in the actual amounts of the components of the system

question

Equilibrium position

answer

Relative concentrations of the reactants and products at equilibrium

question

Le Châtelier's Principle

answer

If a stress is applied to a system in dynamic equilibrium, the system changes in a way that relieves the stress. Stress is that upset the equilibrium of a chemical system include changes in the concentration of reactants or products, changes in temperature, and changes in pressure.

question

equilibrium constant (Keq)

answer

the ratio of product concentrations to reactant concentrations is at equilibrium, with each concentration raised to a power equal to the number of moles of that substance in the balanced chemical equation. A value of Keq greater than one means that products are favored over reactants. A value of Keq less than 1 means that reactants are favored over products.

question

solubility product constant (Ksp)

answer

the product of the concentrations of the ions each raised to a power equal to the coefficient of the ion in the dissociation equation. The smaller the numerical value of the solubility product constant, the lower the solubility of the compound. If the product of the concentrations of two ions in the mixture is greater than the Ksp of the compound formed from the ions, a precipitate will form

question

common ion

answer

an ion that is found in both salts and a solution

question

common ion effect

answer

The lowering of solubility in an ionic compound as a result of the addition of a common ion

question

rate law

answer

An for the rate of a reaction in terms of the concentration of the reactants

question

specific rate constant (k)

answer

A proportionality constant relating to the concentrations of reactants to the rate of the reaction. The value of k is large if the products form quickly; the value is mall if the products form slowly

question

First- Order reaction

answer

The reaction rate is directly proportional to the concentration of only one reactant. Rate = k [A]^a x [B]^b

question

elementary reaction

answer

a reaction in which the reactants are converted to products in a single step.

question

reaction mechanism

answer

The series of elementary reactions or steps that take place during the course of a complex reaction

question

Intermediate

answer

a product of one of the steps in the reaction mechanism. It becomes a reactant in the next step.

question

properties of acids

answer

tastes sour, changes the color of an acid - base indicator, is an electrolyte, and produces hydrogen

question

properties of bases

answer

Tastes bitter, though most bases are hazardous to taste; feels slippery, changes the color of an acid - base indicator, electrolyte

question

Arrhenius acids

answer

contain hydrogen ions (H+) when aqueous and a polar bond. Types: monoprotic (one hydrogen atom), diprotic (two hydrogen atoms), triprotic (three hydrogen atoms)

question

Arrhenius bases

answer

contain hydroxide ions (OH-) when aqueous

question

Brohsted-Lowry acids

answer

Hydrogen ion donator

question

Brohsted-Lowry bases

answer

Hydrogen ion acceptor

question

conjugate acid

answer

The particle formed when a base gains a hydrogen ion

question

conjugate base

answer

the particle that remains when an acid has donated a hydrogen ion

question

conjugate acid-base pair

answer

two substances related by the loss or gain of a single hydrogen ion

question

hydronium ion (H3O+)

answer

a water molecule that gains a hydrogen ion and becomes positively charged

question

amphoteric

answer

a substance that can act as both an acid and a base. An example is water

question

Lewis acid

answer

accepts a pair of electrons to form a covalent bond

question

Lewis base

answer

donates a pair of electrons to form a covalent bond

question

self-ionization

answer

In which water molecules produced ions

question

Neutral solution

answer

any aqueous solution in which [H+] and [OH-] are equal

question

ion-product constant for water (Kw)

answer

for aqueous solutions, the product of the hydrogen - ion concentration and the hydroxide - ion concentration equals 1×10 to the -14 power

question

acidic solution

answer

the concentration of H+ is greater than the concentration of OH-. H+ is greater than 1 x 10 to the negative 7 power. pH is less than 7. pOH is greater than 7.

question

basic solution (alkaline solutions)

answer

the concentration of H+ is less than the concentration of OH-. OH- is greater than 1 x 10 to the negative 7 power. pH is greater than 7. pOH is less than 7

question

indicator (HIn)

answer

an acid or base that undergoes dissociation in a known pH range

question

Strong Acid

answer

completely ionized in an aqueous solution. have large Ka values

question

Weak Acid

answer

ionize only slightly in an aqueous solution; the ionization is not complete. have small Ka values

question

Acid dissociation constant (Ka)

answer

the ratio of the concentration of the dissociated (ionized) form of an acid to the concentration of the undissociated (non-ionized) form. Weak acids have small Ka values. Strong acids have large Ka values.

question

strong bases

answer

dissociate completely into metal ions and hydroxide ions in aqueous solution

question

weak bases

answer

react with water to form the hydroxide ion and the conjugate acid of the base

question

Base dissociation constant (Kb)

answer

the ratio of the concentration of the conjugate acid multiplied by the concentration of the hydroxide ion to the concentration of the base. The smaller the Kb value, the weaker the base.

question

neutralization reactions

answer

reactions in which an acid and a base react in an aqueous solution to produce a salt and water. In general, the reaction of an acid with a base produces water and one of a class of compounds called salt, (compound consisting of an anion from an acid and a cation from a base)

question

equivalence point

answer

When the number of moles of hydrogen ions equals the number of moles of hydroxide ions

question

titration

answer

The process of adding unknown amount of solution of known concentration to determine the concentration of another solution

question

standard solution

answer

the solution of known concentration

question

end point

answer

The point at which the indicator changes color; the point of neutralization in a titration

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