Chemistry definitions

Matter

Anything that has both mass and volume

Solid matter

Atoms/molecules pack close together and have a fixed location (do not move)

Liquid matter

Atoms/molecules pack close together but have the ability to move (fixed volume not shape)

Gaseous Matter

Atoms/molecules that have a lot of space and are free to basically move however they want

Composition

Types and amounts of simpler substances that make up a sample of matter

Physical properties

Observes and measures without changing identity of substance (shape, physical state, boiling and freezing points, density, color)

Physical change

Matter undergoes a physical change of state, composition remains constant (water freeing and being boiled)

Chemical properties

Ability of a substance to interact with other substances and change into new substances

Chemical changes

Original substance is converted to a new substance with different physical and chemical properties (iron nails rusting)

Energy

Capacity to do work, cannot be created or destroyed (Law of conservation of energy)

Kinetic energy

Associated with the movement of an object

Kinetic energy formula

KE = ½ mv² (m = mass)

Potential energy

Associated with the position and composition of an object

Thermal energy

A type of kinetic energy associated with temperature of an object that arises from motion of individual atoms/molecules

Kilo (k)

1000, 10³

Centi ( c)

0.01, 10-²

Mili (m)

0.001, 10-³

Avogadro’s Number

6.022 × 10²³ ( 1 mole = this)

Molarity (M) Equation

M = m/L (m = moles, L = liters)

Density equation

D = M/V (M = mass, V = volume)

Intensive physical property

Physical property does not depend on amount of substance

Extensive physical property

Physical properties are dependent on amount of substance (Example: mass and volume)

Accuracy

How close the measure value is to the actual value

Precision

How close a series of measurements is to one another (more decimal places you go out)

Scientific measurements

Every digit is certain except for the last digit which is estimated

Matter

Anything that has mass and takes up space. Composed of particles (atoms, molecules, subatomic particles)

Atoms

Submicroscopic particles that are fundamental building blocks of ordinary matter

Molecules

Substances formed when two or more atoms bond in specific arrangements

Pure substance

Made up of only one component and has a constant composition throughout sample (oxygen gas, water)

Elements

Substances that cannot be chemically broken down into simple substances

Compounds

Substance composed of two or more elements in fixed definite proportions

Mixture

Substance composed of two or more components in proportions that can vary from one sample to another (water and oil)

Heterogenous mixture

Not uniform throughout

Homogeneous mixture

Is uniform throughout

Isotopes

Two atoms of the same identity with a different number of neutrons

Mass number

The sum of the number of neutrons and protons in an atom

Weighted average of isotopes

(Mass number isotope 1 x natural abundance) + (mass number isotope 2 x natural abundance)

Number of neutrons

Mass number (top right) - atomic number (bottom left, and is also number of protons)

Ions

Atoms that gain or lose electrons

Cations

Positively charged ions (metals)

Anions

Negatively charged ions (nonmetal elements)

Chemical bonds

A result from attraction between charged particles (electrons and protons) that compose atoms

Molecule

Formed when two or more elements combine (can be the same or be different)

Compounds

Composed of atoms held together by chemical bonds

Ionic Bonding

Metal and nonmetal (metal becomes cation, nonmetal becomes anion). Transfer of electrons from one atom to another

Ionic compound

Cations (metals) and anions (nonmetals) bound together by ionic bonds

Covalent bonding

Nonmetal and Nonmetal. Sharing of electrons between two atoms.

Type 1 Ionic compounds

Contains a metal whose charge is constant from one compound to another

Binary ionic compounds

Contain only two different elements. Names will take form— Name of cation (metal) then base name of anion (nonmetal) + ide (KCl→Potassium chloride)

Type 2 ionic compounds

Metals that can vary in charge from one compound to another (transition metals, inner transition metals & p-block metals). Charge is indicated with roman numerals)

Oxyanions

Anions containing oxygen and another element. -ate means more oxygen and -ite means less oxygen

Polyatomic ions

Ionic compounds that contain a polyatomic ion rather than a simple anion, named in the same manner as binary ionic compounds. (NaNO2 = sodium nitrite)

Molecular compounds naming

Prefixes given to each element indicate the number of atoms present

Molecular mass/weight

Mass of individual molecule or formula unit

Molecular mass formula

Sum of the masses of the atoms in a single molecule or formula unit

Filtration

Separates components of a mixture based upon differences in particle size. Usually separating precipitate from solution.

Crystallization

Separation is based on differences in solubility of the components in the mixture

Distillation

Separation based upon differences in volatility

Extraction

Separation based on differences in solubility in different solvents

Chromatography

Separation is based on differences in solubility in a solvent versus a stationary phase

Experimental mass analysis of element

% mass of element = molecular mass of element / mass of compound x 100

Empirical formula

Simplest whole-number ratio of the atoms of elements in a compound

Molecular formula

empirical formula x n (n = molar mass/empirical formula molar mass)

Synthesis/Combination

Two or more substances react to form one product

Decomposition

One substance breaks down into two or more substances

Single replacement

An element will replace another element in a compound

Double replacement

An element in one compound will replace another element in the other compound

Combustion

Rapid reactions that produce a flame, most often involves hydrocarbons reacting with oxygen in the air

Stoichiometry

Study of the numerical relationship between chemical quantities in a chemical reaction

Stoichiometric ratio

Conversion factor between the amount in moles of reactant to moles of a product

Mass to mole conversion

Mole = mass(g) / molar mass

Mole to mass conversion

Mass = moles x molar mass

Stoichiometry equation

mass A x (1 mole A/molar mass A) x (stoichiometric ration B:A) x (molar mass B/1 mol B)

Limiting reactant

Reactant that is used up first, stops the reaction from proceeding anymore once it is used

Reactant in Excess

Any reactant that occurs in a quantity greater than is required to completely react with the limiting reactant

Theoretical yield

Amount of product that can be made in a chemical reaction based on amount of limiting reactant

Actual yield

Actual amount of product made in a chemical reaction

Percent yield equation

% = actual yield / theoretical yield x 100

Solutions

Homogeneous mixtures

Solute

Minor component of the solution

Solvent

Major component of the solution

Dilute solutuon

Small amount of solute compared to solvent

Concentrated solution

Large amount of solute compared to solvent

How does solute dissolve

Attractive forces between solute particles holding them together, when solute and solvent mix and attractive forces between them are strong enough the solute dissolves

Salt solutin

Ionic compounds (metal + nonmetal) when dissolved in water

Electrolytes

Materials that dissolve in water and promote the flow of electricity

Nonelectrolytes

Materials that dissolve in water form a solution that will not conduct electricity

Dilution equation

C1V1 = C2V2 or M1V1 = M1V2

Precipitation reactions

Reactions in which a solid forms when two solutions are mixed

Precipitate

Insoluble product formed from reactions between aqueous solutions of ionic compounds

Molecular equation

Equation showing the complete neutral formula for each compound in aqueous reaction

Complete ionic equation

Equation that describes the materials structure when dissolved

Spectator ions

Ions in the solution that are unchanged on both sides of the equation in complete ionic equations

Net ionic equation

The chemical reaction that remains after spectator ions are removed

Neutralization reaction

Acid-base reaction (H+ combines with OH- from base to make water and a “salt”)

Pressure

Force exerted per unit area by gas molecules as they strike surfaces around them (F/A (force/area))

What is gas pressure dependent on

Number of gas particles in volume, volume of container, average speed of gas particles

Concentration of gas molecules

Higher the concentration, greater the pressure

Number of gas molecues

Fewer gas particles lower force and lower pressure, more gas particles higher fore and higher pressure

Conversions between pressure units

1 mmHg = 1 torr

760 mmHg = 1 atm

760 torr = 1 atm

101.3 kpa = 1 atm