Studied by 58 peoplechemistry
the study of composition, properties, and interactions of matter
macroscopic domain
large enough to be sensed directly by human sight or touch
microscopic domain
often visited in the imagination. Some aspects are visible through sophisticated instruments
symbolic domain
specialized language representing components of the macroscopic and microscopic domains. Chemical symbols, chemical formulas, chemical equations, graphs, drawings, and calculations.
matter
anything that occupies space and has mass
plasma
the fourth state of matter that occurs naturally in the interior of stars, can also be made using high energy sources. A gaseous state of matter that contains electrically charged particles.
substance
a form of matter that has definite composition and distinct properties
mixture
a physical combination of two or more substances
homogeneous mixture
is uniform throughout; also called a solution
heterogeneous mixture
is not uniform throughout; has multiple different parts
Law of Conservation of Matter
there is no detectable change in the total quantity of matter present when matter converts from one type to another (a chemical change) or changes among solid, liquid, or gaseous states (a physical change).
mixture
can be separated by physical means into its components without changing the identities of the components.
atom
is the smallest particle of an element that has the properties of that element and can enter a chemical combination
molecule
consists of two or more atoms joined by strong forces called chemical bonds; always contains the same elements in the same proportions by mass and by atom numbers
physical property
one that can be observed and measured without changing the identity of the substance
physical change
one in which the state of matter changes, but the identity of the matter does not change
chemical property
one a substance exhibits as it interacts with another substance
chemical change
one that results in a change of composition; the original substances no longer exists
extensive property
depends on the amount of matter. The value is directly proportional to the amount of matter in question.
intensive property
does not depend on amount of water
measurements
provide much of the information informing the hypothesis, theories, and laws describing the behavior of matter
english system
has units such as the foot, gallon, pound, etc.
metric system
includes units such as meter, liter, kilogram, etc.
international system of units
metric system
conversion factor
a fraction in which the same quantity is expressed one way in the numerator and another way in the denominator; created from an equality statement
Celcius scale
freezing point (pure water) 0 degrees; Boiling point (pure water) 100 degrees
Kelvin scale
the "absolute" scale; lowest possible temperature Tk=TC+273.15
Fahrenheit scale
common in the United States, freezing point (pure water) 32 degrees Celcius, boiling point (pure water) 212 degrees Celcius TF=(9/5)(TC)+32
density
ratio of mass to volume; density is mass divided by volume
SI-derived unit
kilogram per cubic meter
Significant figures
the meaningful digits in a reported number
uncertain digit
the last digit in a measured number
exact numbers
considered to have an infinite number of significant figures and do not limit the number of significant figures as a result
accuracy
tells us how close a measurement is to the true value
precision
tells us how close a series of replicate measurements are to one another
dimensional analysis
the use of conversion factors in problem solving; called the factor-labeled method
Dalton's Atomic Theory
all matter is composed of tiny particles called atoms
all atoms of a given element have identical chemical properties
atoms form chemical compounds by combining in whole-number ratios
Atoms can change how they are combined, but they are neither created nor destroyed in ORDINARY chemical reactions.
Law of Conservation of mass
there is no detectable change in mass during an ordinary chemical reaction
Law of Constant Composition/ Definite Proportion
a chemical compound always contains the same elements with the same proportions by the number of the atoms of the constituent elements; a chemical compound always contains the same elements with the same proportions by mass, regardless of its size, shape, and physical state of the compound
Thomson
discovered in the late 1800s that cathode ray are a stream of negatively charged particles now known as electrons. By varying the electric field and measuring the degree of deflection of cathode rays, determined the electron charge-to mass ratio to be : 1.76*10^11 C/Kg
R.A. Millikan
determined the charge on an electron by examining the motion of tiny oil drops. 1.6022*10^-9 C
Ernest Rutherford
used the positively charged particles that consists of two protons and two neutrons to study the structure of atoms. proposed a nuclear model: positive charge is concentrated in the nucleus, the nucleus accounts for most of an atom's mass and is an extremely dense central core within the atom
isotope
an element can have different types of atoms that have different masses but are chemically indistinguishable in ordinary chemical process. atoms of the same element differing in mass. have the same number of protons and electrons, but different neutrons.
protons
positively charged particles found in the nucleus
neutrons
electronically neutral particles in the nucleus. slightly larger than protons
electrons
negatively charged particles distributed around the nucleus
atomic number
the number of protons in the nucleus
mass number
total number of protons and neutrons
atomic mass
the mass of an atom in atomic mass units (amu)
molecule
a combination of at least two atoms in a specific arrangement held together by chemical forces; may be an element or a compound
Law of Definite Proportions
different samples of a given compound always contains the same elements in the same ratio
molecular formula
shows the exact number of atoms of each element in a molecule
structural formula
shows not only the elemental composition, but also the general arrangements
empirical formula
the lowest whole-number ratio of elements
polyatomic ions
consists of a combination of two or more atoms
oxoanions
polyatomic anions that contain one or more oxygen atoms and one atom (the "central atom") of another element
acid
a substance that produces hydrogen ions when dissolved in water
oxoacids
when dissolved in water, produce hydrogen ions and the corresponding oxoanions; can be monoprotic (one ionizable hydrogen) or polyprotic (more than one ionizable hydrogen)
hydrate
a compound that has a specific number of water molecules within its solid structure
anhydrous
the compound no longer has water molecules associated with it
formula mass
the sum of the average atomic masses in atomic mass units (amu) of all the atoms represented in the substance formula
formula mass of a molecular compound
the average mass of an individual molecule in atomic mass units (amu); also called molecular mass and molecular weight
mole
defined as the amount of a substance that contains as many elementary entities as there are atoms in exactly 12 g of carbon-12
molar mass
the mass in grams of one mole of the substance
percent composition by mass
a list of the percent by mass of each element in a compound; percent mass of an element= natomic mass of an element/molecular or formula mass of a compund100%
molarity
the number of moles of solute per liter of solution L=mol/M, mol=M*L
dilution
M1L1=M2L2; the process of preparing a less concentrated solution from a more concentrated one
serial dilution
C1V1=C2V2
Group 1 elements
alkali metals; Li, Na, K, Rb, Cs, Fr
Group 2 elements
alkaline earth metals; Be, Mg, Ca, Sr, Ba, Ra
Group 15 elements
pnictogens; N, P, As, Sb, Pi, Mc
Group 16 elements
chalcogens; O, S, Se, Te, Po
Group 17 elements
halogens; F, Cl, Br, I, At
Group 18 elements
noble gases; He, Ne, Ar, Kr, Xe, Rn
Groups 3-12 elements
Transition elements
Note
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