Ap Chemistry Unit 1

(Pure) Substance

Material with constant, distinct properties and composition.

Element

A substance that can't be broken down into simpler substances.

Compound

A substance composed of two or more elements in a fixed ratio

Mixture

A combination of different substances

Homogeneous Mixture

Uniform throughout (Appears to have only one phase throughout)

Heterogenous Mixture

Not uniform throughout (Has more than one phase)

Physical Property

Property that can be seen or measured without changing the identity of the component(s).

Chemical Property

Property that can only be observed by changing the material into a new substance.

Filtration

Separates mixtures based on differences in state or size.

Distillation

Separates mixtures based on differences in boiling points.

Chromatography

Separates mixtures based on differences in affinity.

Ampere

Electric Currency

Candela

Luminous Intensity

How to find Density

Mass / Volume

How to find Percent Error

(Experimental Value - Theoretical Value)/Theoretical Value * 100 = % Error

Law of Conservation of Mass

For a chemical or physical process, total mass of reactants equals total mass of products

Law of Constant Composition

The mass ration of elements in a compound is always the same

Law of Multiple Proportions

When two elements can be combined to make two different compounds, and if samples of these two are taken so the masses of one of the elements in the two compounds are the same in both samples, than the radio of the masses of the other element in those compounds will be a ratio of small whole numbers.

Michael Faraday

Electrical current could cause chemical reaction

Sir Williams Crooks

Developed cathode ray tube

Scientific Method

the process of studying natural phenomena, involving observations, forming laws and theories, and test of theories by experimentation

measurement

a quantitive observation that consists of a number and a scale

hypothesis

one or more assumptions put forth to explain the observed behavior of nature

theory

a set of assumptions put forth to explain some aspect of the observed behavior of matter

model

a set of assumptions put forth to explain the observed behavior of matter. The models of chemistry usually involve assumptions about the behavior of individual atoms or molecules

SI System

International System of Units based on the metric system and units derived from the metric system

mass

the quantity of matter in an object

weight

the force exerted on an object by gravity

significant figures

the certain digits and the first uncertain digit of a measurement

factor-label method

an equivalence statement between units used for converting from unit to another especially used in dimensional analysis

dimensional analysis

what is used to convert a given result from one system of units to another

density

a property of matter representing the mass per unit volume

matter

Anything that has mass and takes up space

homogenous mixture

mixtures that have visibly indistinguishable parts

heterogeneous mixture

mixtures that have visibly distinguishable parts

solution

a homogenous mixture

pure substance

a substance with constant composition

physical change

a change in the form of a substance, but not in its chemical composition; chemical bonds are not broken in a physical change

distillation

a method for separating the components of a liquid homogeneous mixture that depends on differences in the ease of vaporization (boiling point) of the components

chromatography

the general name for a series of methods for separating mixtures by employing a system with a mobile phase and a stationary phase

compound

a substance with constant composition that can be broken down into elements by chemical processes

chemical change

a given substance becomes a new substance or substances with different properties and different composition

atomic masses

sometimes called atomic weights by chemists, since mass is often determined by comparison to a standard mass—a process called weighing

electron

a negatively charged particle

nucleus

the small, dense center of positive charge in an atom

proton

a positively charged particle in an atomic nucleus

neutron

a particle in the atomic nucleus with mass virtually equal to

the proton's but with no charge

isotopes

atoms with the same number of protons but different numbers of neutrons

atomic number

the number of protons in the nucleus of an atom

mass number

the total number of protons and neutrons in the atomic nucleus of an atom

chemical bond

the force or, more accurately, the energy, that holds two atoms together in a compound

covalent bond

a type of bonding in which electrons are shared by atoms

molecule

a bonded collection of two or more atoms of the same or different elements

chemical formula

the representation of a molecule in which the

symbols for the elements are used to indicate the types of atoms present and subscripts are used to show the relative numbers of atoms

structural formula

the representation of a molecule in which the relative positions of the atoms are shown and the bonds are indicated by lines

ion

an atom or a group of atoms that has a net positive or negative charge

cation

a positive ion

anion

a negative ion

ionic bond

the electrostatic attraction between oppositely charged ions.

polyatomic ion

an ion containing a number of atoms

periodic table

a chart showing all the elements arranged in columns with similar chemical properties.

metal

an element that gives up electrons relatively easily and is lustrous, malleable, and a good conductor of heat and electricity

nonmetal

an element not exhibiting metallic characteristics. Chemically, a typical nonmetal accepts electrons from a metal

group (family)

a vertical column of elements having the same valence electron configuration and showing similar properties

period

The horizontal rows of elements in the periodic table

binary compounds

a two-element compound

chemical stoichiometry

the calculation of the quantities of material consumed and produced in chemical reactions

mass spectrometer

an instrument used to determine the relative masses of atoms by the deflection of their ions on a magnetic field

mole

the number equal to the number of carbon atoms in ex- actly 12 grams of pure 12C: Avogadro's number. One mole represents 6.022 1023 units

Avogadro's Number

the number of atoms in exactly 12 grams of pure 12Carbon, equal to 6.022 x 10^23

molar mass

the mass in grams of one mole of molecules or formula units of a substance; also called molecular weight

mass percent

the percent by mass of a component of a mixture (11.1) or of a given element in a compound

empirical formula

the simplest whole number ratio of atoms in a compound

molecular formula

the exact formula of a molecule, giving the types

of atoms and the number of each type

chemical equation

a representation of a chemical reaction showing the relative numbers of reactant and product molecules

reactants

a starting substance in a chemical reaction. It appears to the left of the arrow in a chemical equation

products

a substance resulting from a chemical reaction. It is shown to the right of the arrow in a chemical equation

Mole Ratio

the ratio of moles of one substance to moles of another substance in a balanced chemical equation

Limiting Reactant (Reagent)

the reactant that is completely consumed when a reaction is run to completion

Solid

Retains a fixed shape and volume: Rigid- particles locked in space, not easily compressible: Little free space between particles, Doesn't flow easily

Liquid

Assumes the shape of the container that it is in: Particles can move/slide past each other, Not easily compressible: Little free space between particles, Flows easily

Gas/Vapor

Easy to compress: Far more space between particles, Expand to fill their containers: Particles can move past each other, and Occupy far more space that the other states of matter

Kelvin

The S.I. unit for temperature that equates to Celsius + 273.15.

Kilogram

The SI unit for Mass

Meter

The SI unit for Length

Second

The SI unit for Time

Mole Unit

The SI unit for the amount of a substance

J.J. Thomson

Determined cathode ray tube emitted electrons not negatively charged particles which helped understanding of the atom.

Ernest Rutherford

Gold foil experiment, discovered nucleus and that the core of an atom consisted of protons

Accuracy

how close a measurement is to the true value

Precision

how close a group of measurements are to each other

Atoms

Building blocks of matter

intensive property

a property that does not depend on the amount of matter present, such as pressure, temperature, or density

extensive property

a property that depends on the amount of matter in a sample

Temperature

A measure of the average energy of motion of the particles of a substance. It is proportional to the kinetic energy in a system.

percent composition

the percentage by mass of each element in a compound