How can we help?

You can also find more resources in our Help Center.

66 terms

General Chemistry I: Test 1 Terms and Ideas

STUDY
PLAY
OFLET
OBSERVATIONS lead to FACTS which are summarized into LAWS which are EXPLAINED by THEORIES
Law
a general statement based on observations to which no exceptions are known
Theory
an explanation for a law
Physical Property
properties that do not change composition when measured
Chemical Property
properties observed when matter changes composition
Chemistry:
Chemistry is a central, empirical science that studies the physical and chemistry properties of matter, the physical and chemical changes matter undergoes and the energy associated with those changes.
Specific Heat
the amount of heat necessary to raise the temperature of a specific amount of a substance one degree Celsius with no change in state. Expressed in J/g.
Chemical Formula
composition of elemental symbols that indicates the chemical composition of a substance
Density
mass per unit volume
Atoms
the smallest particle of an element that maintains its chemical identity through all chemical and physical changes
Molecules
the smallest particle of an element that can have a stable independent existence
Atomic Weight
weighted average of the masses of the constituent isotopes of an element; the relative mass of atoms of different elements
Ion
an atom or group of atoms that carries a charge
Structural Formula
a representation that shows how atoms are connected in a compound
Reactants
substances consumed in a chemical reaction
Products
substances produced in a chemical reaction
Simplest Formula
the smallest whole-number ration fo atoms present in a compound (aka empirical formula)
Molecular Formula
a formula that indicates the actual number of atoms present in a molecule of a molecular substance
Atomic Mass Unit
a unit used for stating atomic and formula weights (one-twelfth of the mass of an atom of the carbon-12 isotope)
Mole
6.022 x 10^23 (Avogadro's number) of a substance. the mass in grams of one mole is equal to the molecular weight of the substance
Limiting Reactant
a substance that stoichiometrically limits the amount of products that can be formed in a reaction
Chemical Change
a change in which one or more new substances are formed
Kinetic Energy
energy that matter possesses by virtue of its motion
Potential Energy
energy that matter possesses by virtue of its position
Gas
state of matter that moves to fill its entire container
Liquid
state of matter that has a set fluid volume
Solid
state of matter that is rigid and holds its shape
Matter
anything that has mass and can be observed (with some exceptions: light)
Water*
H2O
Hydrogen Peroxide*
H2O2
Sulfuric Acid*
H2SO4
Nitric Acid*
HNO3
Acetic Acid*
CH3COOH
Ammonia*
NH3
Carbon Monoxide*
CO
Carbon Dioxide*
CO2
Sulfur Dioxide*
SO2
Sulfur Trioxide*
SO3
Methane*
CH4
Ethane*
C2H6
Propane*
C3H8
Butane*
C4H10
Pentane*
C5H12
Methanol*
CH3OH
Ethanol*
CH3CH2OH
Hydrocarbon + O2 --->
CO2 + H2O
Law of Constant Composition
different samples of any pure compound contain the same elements in the same proportions by mass
Law of Conservation of Energy
energy cannot be created or destroyed in a chemical reactions or in a physical change, it must be changed from one form to another
Law of Conservation of Matter
no detectable change occurs in the total quantity of matter during a chemical reaction or a physical change
Dalton's Theory
1. made of atoms 2. atoms are identical and differentiable 3. atoms cannot be created or destroyed or transformed 4. compounds in whole number ratios 5. compound's atoms are constant
Theoretical Yield Concept
*
Mass of Reactants Concept
*
Percent Yield Formula
*
Finding Molecular Weights from Atomic Weights
*
Finding the Simplest Formula given Elemental Percentages
*
Identifying Limiting Reactants
*
Calculate the Specific Heat from Temp changes
(heat in J)/(mass)(temperature change in C)
Know Mole Concepts
*
Finding Percent Composition from Formula
=(g of x)/(g of total) x 100%
Tips on how to balance molecular equations
1. one timers 2. common elements across compounds (biggest coefficient first) 3. free/uncombined elements go last
Know how to distinguish between phases at macroscopic level
Macroscopically, what distinguishes a solid? hardness, shape is maintained what distinguishes a liquid? adapts to container shape what distinguishes a gas? occupies entire volume of container
Know how to distinguish between phases at microscopic level
Macroscopically, what distinguishes a solid? hardness, shape is maintained what distinguishes a liquid? adapts to container shape what distinguishes a gas? occupies entire volume of container
Physical Change
a change in matter than does not alter composition or identity
Percent Yield
=(actual yield)/(theoretical yield) x 100%
Molarity
=(number of moles of a solute)/(number of liters of a solution)
Law of Conservation of Matter and Energy
the amount of matter and energy in the universe is fixed