Chem 1A - First Semester Vocab

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Physical Property

quality or condition of a substance that can be observed or measured without changing the substance's composition; properties that do not involve substances changing into another substance

Chemical Property

the ability of a substance to undergo a chemical reaction and to form new substances; substance changing into another substance

Classification of Matter

matter is either pure substance or mixture; pure substance is either element or compound; mixture is either homogenous or heterogenous


cannot be converted to a simpler form by a chemical reaction; ex. hydrogen


combination of two or more elements in a definite, reproducible way; ex. water


combination of two or more pure substances; ex. blood


uniform composition; ex. gasoline


non-uniform composition; ex. salad dressing


the smallest unit of an element that has all of the properties of an element


the smallest unit of a pure substance that has the properties of that substance; no net electrical charge, made of nonmetals

Dalton's Atomic Theory

all matter/elements is/are composed of atoms, all atoms of an element are alike, law of definite composition - simple whole number ratios, atoms cannot be created or destroyed


small, dense, positively charged in the center of the atom, discovered by Rutherford


subatomic particles that surround the nucleus and have negative charge, much less than 1 amu

Periodic Table

arrangement of elements according to similarities in their properties; symbol, element name, atomic number, atomic mass; arranged by atomic number, put together by Mendeleev

Atomic Number

number of protons in the nucleus of an element


have high electrical conductivity and a high luster when clean, ductile and malleable, left side of periodic table; form cations, solid at room temperature


nonlustrous and poor conductors of electricity, right side of periodic table


have properties of both metals and nonmetals; middle of periodic table

Names of Periodic Table

horizontal rows: periods, vertical columns: groups; Group 1A: alkali metals, Group 2A: alkaline earth metals Group B: transition & inner transition metals, Group 7A: halogens, Group 0: noble gases

Diatomic Molecules

molecules that contain two atoms

Homo-atomic Molecule

molecule with two or more atoms of one elements

Hetero-atomic Molecule

molecule containing at least two atoms of two or more elements

Ionic Compounds

formula tells the simple ratios of cations to anions, called formula units, formed with a metal, have a metal and nonmetal, form cations to anions


postively charged ion, have lose electrons


negatively charged ions, have gained electrons

Polyatomic Ions

special class of ions where a group of atoms tend to stay together; ex. sulfate

Cation + Anion (Inorganic Compound)

given name; ex. sodium chloride

Compound Contains Polyatomic Ion (Inorganic Compound)

given name; ex. ammonium sulfate

Transition Metal Compound

roman numerals indicate charge of metal, ex. copper (II) oxide

Molecular Compounds

name elements in order they appear in the formula, use prefixes to name how many atoms of each type; ex. carbon dioxide

SI Units

used by scientists to speak the same language for measurement

Gram (g)
Meter (m)
Liter (L)
Second (s)
Joule (J)

In metric units:
Mass =
Length =
Volume =
Time =
Energy =

Kilogram (kg)
Meter (m)
Second (s)
Kelvin (K)
Mole (mol)

In SI units:
Mass =
Length =
Time =
Temperature =
Amount =

Metric Prefixes


Factor Labeling Method

use conversion factors and keep track of units, cancel out units along way to convery amounts


how close to the true value


how close to each other

Significant Figures

measurement including all of the know digits, plus one more digit that is estimated


measure of the quantity of matter present, constant regardless of location, SI unit is kg, everyday unit is g


amount of space an object occupies, base unit L, common unit mL = cm^3

Extensive Property

depend on quantity of sample measured; ex. mass and volume

Intensive Property

Independent of sample size; ex. density, melting, boiling point

Density (D = M/V)

intensive property of a sumstance based on two extensive properties, g/cm^3, g/mL

Specific Gravity

density of a substance compared to a reference substance (usually water at 4 degrees C)

C = K - 273

Convert C to K


6.02 x 10^23 representative particles

Molar Mass

mass in grams of one mole of that substance

Molecular Mass

total mass for all elements in a molecular compound

Formula Mass

total mass for all elements in an ionic compound

Models of the Atom

Thomson's Atomic Model- believed that electrons were embedded in positively charged particles; Rutherford's Atomic Model- the atoms is mostly empty space, all of the positive charge and mass is concentrated in the nucleus, the nucleus is composed of protons & neutrons, electrons are distributed around the nucleus and occupy most of the volume, and his model is called the "nuclear model."


positively charged subatomic particles, 1 amu


neutrally charged subatomic particles, 1 amu

Mass Number

total number of protons and neutrons in an atom


atoms of the same element with different numbers of neutrons, have different mass numbers

Atomic Mass (AMU)

one-twelfth the mass of a carbon-12 atom

% abundance

how often an element occurs in nature

Word equations

qualitative, show the reactants you need to make your product(s), use words instead of chemical symbols

Writing Chemical Equations

use an arrow (means yield) to separate reactants and products, write catalysts over the arrow if they're involved; identify physical states, such as solid (s), liquid (l), gas (g), and aqueous solution (aq)

Balancing Equations

use coefficients (numbers placed in front of symbols) so that you have the same number of each element in the reactant and product sides

Combination Reaction

2 substances combine to make one compound
2K + Cl2 yields ?

Decomposition Reaction
Na + Cl2

one reactanct breaks apart into two or more elements of compounds, energy is usually required
NaCl yields ?

Single Replacement Reaction
K + NaCl

one element replaces another, reactants must be an element and a compund
Na + KCl yields?

Double Replacement Reaction
Fe(OH)3 + NaCl

two things replace each other, reactants must be ionic compunds in aqueous solution
NaOH + FeCl3 yields?

Combustion Reaction
8CO2 + 10H2O
8CO + 10H2O

add oygen, burning normally composed of C, H and maybe O reacted with O
if complete, the products will be CO2 and H20
if incomplete, the products will be CO (possibly C) and H2O
2C4H10 + 13O2 (complete) yields?
2C4H10 + 9O2 (incomplete) yields?

Skeleton Equations

chemical equations that do not indicate the relative amounts of reactants and products in the equation

Law of Conservation of Matter

matter cannot be created or destroyed, important for stoichiometry

Chemical Equations

arrows separate formulas of reactants from formulas of products

Mole Calculations

if you know the number of moles of one substance you can determine the number of moles of all the other substances with a balanced equation

Mass to Mass Calculations

from the mass of a product or reactant the mass of any other reactant or product can be calculated

Mole to Gram Conversionss

find the number of grams in one mole of the substance and multiply that by the number of moles you have. Ex.- 3 moles x 2.02g/1mol = 6.06 grams

Limiting Reagent

material that is in shortest supply based on a balanced chemical equation

Theoretical Yield

what the balanced equation should make

Actual Yield

what you actually get in the lab when the chemicals are mixed

Percent Yield

Actual/Theoretical x 100

Empirical Formula

simplest formula that shows the ratios of the number of atoms of each element in a compound
for H202 it is HO

Molecular Formula

shows the actual number of each type of atom in a molecule, can be found from molecular mass


quantity of heat needed to raise the temperature of 1 g of pure water 1 degree C


measurement of heat into or out of a system for chemical and physical processes, heat released = heat absorbed

Chemical Potential Energy

stored energy - ability to do work, stored in chemical bonds

Endothermic Process

heat flowing into a system from its surroundings, positive, q is positive, system gains heat


capacity for doing work or supplying heat, represented by q, measured in joules


heat content of system at constant pressure, can't be measured directly

Exothermic Process

heat flowing out of a system to it surroundings, negative, q is negative, system loses heat


energy that transfers from one object to another because of a temperature difference between them, represented by q, flows from warmer to colder objects

Heat Capacity

amount of heat needed to increase the temperature of an object exactly 1 degree C


everything else in the universe not focused upon


part of the universe on which you focus your attention


study concerned with the heat changes that occur during chemical reactions


system and surrounding together

Specific Heat

amount of heat it takes to raise the temperature of 1 g of the substance 1 degree C, for water 4.184, lower for metals (shortened name)

Specific Heat Capacity

amount of heat it takes to raise the temperature of 1 g of the substance 1 degree C, for water 4.184, lower for metals


SI unit of heat and energy, 4.184 _____ = 1.00 calorie

Law of Conservation of Energy

in any physical or chemical process energy is neither created nor destroyed

Atomic Mass

the weighted average of the masses of the isotopes of an element

Elemental Symbol

one or two letters that represent an element on the periodic table

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