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95 terms

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
Element
cannot be converted to a simpler form by a chemical reaction; ex. hydrogen
Compound
combination of two or more elements in a definite, reproducible way; ex. water
Mixture
combination of two or more pure substances; ex. blood
Homogenous
uniform composition; ex. gasoline
Heterogenous
non-uniform composition; ex. salad dressing
Atom
the smallest unit of an element that has all of the properties of an element
Molecule
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
Nucleus
small, dense, positively charged in the center of the atom, discovered by Rutherford
Electrons
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
Metals
have high electrical conductivity and a high luster when clean, ductile and malleable, left side of periodic table; form cations, solid at room temperature
Non-metals
nonlustrous and poor conductors of electricity, right side of periodic table
Metalloids
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
Cations
postively charged ion, have lose electrons
Anions
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
Mega
Kilo
Hecto
Deka
Deci
Centi
Milli
Micro
10^6
10^3
10^2
10^1
10^-1
10^-2
10^-3
10^-6
Factor Labeling Method
use conversion factors and keep track of units, cancel out units along way to convery amounts
Accuracy
how close to the true value
Precision
how close to each other
Significant Figures
measurement including all of the know digits, plus one more digit that is estimated
Mass
measure of the quantity of matter present, constant regardless of location, SI unit is kg, everyday unit is g
Volume
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
Mole
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."
Protons
positively charged subatomic particles, 1 amu
Neutrons
neutrally charged subatomic particles, 1 amu
Mass Number
total number of protons and neutrons in an atom
Isotopes
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
2KCl
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
H202
calorie
quantity of heat needed to raise the temperature of 1 g of pure water 1 degree C
Calorimetry
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
Energy
capacity for doing work or supplying heat, represented by q, measured in joules
Enthalpy
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
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
Surroundings
everything else in the universe not focused upon
System
part of the universe on which you focus your attention
Thermochemistry
study concerned with the heat changes that occur during chemical reactions
Universe
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
Joule
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