CH 1010 Exam 1 @ Clemson University

Matter

anything that occupies space and has mass

Solid

definite shape and volume

Liquid

definite volume but flows to assume the shape of its container

Gas

neither definite volume nor shape; expands to fill its container

Pure substances

cannot be separated into simpler substances by physical processes

Mixtures

combination of two or more pure substances

Mixtures

can be seperated by a physical process

Compound

substance that can be decomposed by a chemical process

Element (pure substance)

substance that cannot be decomposed by a chemical process

Compounds

made up of different atoms

Elements

made up of same atoms

Homogenous Mixture

mixture with uniform appearance and composition throughout

Heterogenous Mixture

mixture with uniform appearance and composition throughout

Theory

explains the patterns of a natural phenomena

Hypothesis

possible answer to a scientific question related to an observation

Law

describes a natural phenomena and relationships

Volume

amount of space occupied by an object

Density

mass/volume

Accuracy

How close to the true value a given measurement is

Precision

How well a number of independent measurements agree with each other

kg

SI unit of mass

m

SI unit for length

K

SI unit for temperature

mol

SI unit for amount of substance

273.15

To convert between Kelvin and Celsius use K=C+#

1 ml

1 cm^3

particulate

representation: one molecule of blank

macroscopic

representation: 1 g of blank

Scientific Method

A logical, systematic approach to the solution of a scientific problem

Exothermic

energy flows from a system into its surroundings

Endothermic

energy flows from the surroundings into the system

Heat

energy transferred between objects that are at different temperatures

Thermal Energy

portion of total internal energy of system that is proportional to its absolute temperature

Temperature

measure of thermal energy

Kinetic

Energy of motion

Potential

Energy that is stored

Thermal

heat energy classified as kinetic

Law of Mass Conservation

Mass is neither created nor destroyed in chemical reactions

Law of Definite Proportions

Different samples of a pure chemical compound always contain the same proportion of elements by mass

Law of Multiple Proportions

Elements can combine in different ways to form different chemical compounds; whose mass ratios are simple whole-number multiples of each other.

Dalton's Atomic Theory

matter is composed of small particles called atoms

Dalton's Atomic Theory (Wrong)

Atoms of the same element are identical in shape and mass, but differ from the atoms of other elements.

Dalton's Atomic Theory

Atoms of an element cannot be changed into atoms of a different element (by chemical reactions). Atoms cannot be created or destroyed in chemical reactions.

Dalton's Atomic Theory

Atoms of different elements may combine with other atoms in fixed, simple, whole number ratios to form compounds. A given compound always has the same relative number and kind of atoms.

Nucleus

positively charged center of atom that contains nearly all atom's mass

Proton

subatomic particle, present in the nucleus of an atom, that has a relative charge of 1+ and a mass number of 1

Neutron

electrically neutral (uncharged) subatomic particle with a mass number of 1

Electron

subatomic particle that has a relative charge of 1− and essentially zero mass

period (of elements)

elements in same row of periodic table

group (of elements)

elements in same column of periodic table that HAVE SIMILAR PROPERTIES

Z

Atomic Number

A

Mass Number

Z

number of protons in the nucleus of an atom

A

number of protons or neurons in the nucleus

neutrons

A-Z=

Average Atomic Mass

weighted average of masses of all isotopes of an element

Isotope

atoms of an element containing the same number of protons but different numbers of neutrons

Ion

atom or molecule that has a positive or negative charge

Cation

positive ion

Anion

negative ion

Ionic solid

solid consisting of monatomic or polyatomic ions held together by ionic bonds

Mole

amount of substance

Avogadro

6.0221 × 10^23

Electromagnetic Radiation

any form of radiant energy in the electromagnetic spectrum

Wavelength Inc

Gamma rays, X-rays, UV, Visible, IR, Microwaves, Radio waves

frequency Inc

Radio waves, Microwaves , IR, Visible, UV, X-rays, Gamma rays

emission spectra

set of wavelengths emitted by an element

Absorption spectra

set of wavelengths taken in by an element

photoelectric effect

release of electrons from a material as a result of electromagnetic radiation striking it

Work function

threshold energy of electrons needed to dislodge an electron from the surface of a material

Threshold Frequency

minimum frequency of light required to produce the photoelectric effect

Quantized

having values restricted to whole-number multiples of a specific base value

Quantum

smallest discrete quantity of a particular form of energy

Photon

quantum of electromagnetic radiation

Quantum Number

one of four related numbers that specify the energy, shape, and orientation of orbitals in an atom and the spin orientation of electrons in the orbitals

orbital

Regions in an atom where the probability of finding an electron is high

Shell

orbitals with the same value of n are in the same

Subshells

orbitals with the same values of n and l are in the same

Zeff

attraction toward the nucleus experienced by an electron in an atom

Orbital square

Probability of finding electron within a specific region of space