Physical Science: Chemistry Flashcards
Solid Sphere Model
Dalton’s model of the atom as solid and indivisible
Atoms
the smallest unit of an element that has properties of that element
carbon atom
Solute
The material in a solution that is dissolved in the solvent
The sugar in lemonade
Molarity (M)
the concentration of a solute per liter of solvent
Solution
a mixture in which one substance dissolves in another
simple syrup (sugar and water)
Heterogeneous Mixture
a mixture that is not uniformly mixed
granola with raisins at the bottom
Saturated
A solution that cannot dissolve any more solute
Neutron
neutral particle found in the nucleus of atoms
Compound
groups of two or more different elements held together by ionic or molecular bonds
NaCl and H2O
Proton
positively charged particle found in the nucleus of atoms
Solvent
a substance which dissolves other substances
if salt is dissolved in water, water is the solvent.
Nuclear Model
Rutherford discovered the nucleus and that protons were located here
Electron
low-mass, negatively charged particle; surrounds the nucleus of an atom
Quantum Model
Schrodinger theorized that the electrons move in clouds around the nucleus
Supersaturated
A solution that was saturated and when heated has the ability to dissolve more solute and then it is cooled rapidly
Concentrated
Contains more solute than a diluted solution
Pure Substance
a substance that consists of only one type of atom or molecule
helium gas
Diluted
Contains less solute than a concentrated solution
Planetary Model
Bohr identified that electrons orbited the nucleus in a fixed orbital
Nucleus (of the Atom)
the positively charged, small, central core of an atom; made of protons and neutrons
Plum Pudding Model
Created by JJ Thompson, the protons, neutrons and electrons floated around the atom like fruit in a pudding
Unsaturated
A solution that has the ability to dissolve more solute
Emission Spectrum
A series of colored lines of different wavelengths (or frequencies) produced when electrons in atoms fall from higher to lower energy levels
Ground State
the lowest-energy arrangement of electrons in an atom
Element
an atom with a unique number of protons in its nucleus
iron
Mixture
a substance in which the atoms, molecules, or particles of two or more different materials are mixed but not chemically combined
salad
Homogeneous Mixture
a mixture with the same ratio of parts throughout the mixture
salt dissolved in water
Photoelectric Effect
Electrons are ejected from a metal when illuminated with light at a high enough frequency
Entanglement
Entangled particles instantly share information with each other even when separated by a great distance
Matter
anything that has mass and takes up space
mud
Metallic Bond
A bond between 2 metal atoms that occurs when electrons are released into the shared area and the atoms are attracted to the space.
Percent Composition
The atomic mass of the desired element divided by the total atomic mass of the molecule and multiplied by 100
Triple Bond
An atomic bond between atoms that share three pairs of electrons
N ≡ N
Cation
A positively charged atom that has given up an electron
Avogadro’s Number
the number of atoms in 1 mole of carbon-12.
Double Bond
An atomic bond between atoms that share two pairs of electrons
C = O
Empirical Formula
Shows the ratio of atoms in a molecule, not the actual number of molecules.
Chemical Formula
written expressions of a molecule; tells the number of atoms of each type of element in one molecule
Moles of Atoms
The atomic mass of the molecule divided by Avogadro’s number
Anion
A negatively charged atom that has gained an electron
Polar Bond
A bond between 2 atoms in which one has a slightly stronger pull on the shared electron resulting in oppositely charged poles
Polyatomic Ions
Molecules with a non-zero charge that form from more than one atom
OH-
Ionic Bond
a chemical bond between oppositely charged atoms when electrons are removed from one atom and given to an atom of another element
salt (NaCl)
Electron Dot
Shows only the number of valence electrons in an atom.
Molecular Bond / Covalent Bond
a chemical bond formed when two atoms share their outer electrons; formed between two nonmetal atoms
bond between carbon and oxygen (CO2)
Hydrogen Bond
a weak attraction between hydrogen and some other element in another compound
hydrogen bonds attach water molecules to other water molecules
Molecular Formula
Shows the actual number of atoms, not the ratio as in the empirical formula.
water is H₂O which means there are 2 hydrogen atoms and 1 oxygen atom in each atom
Pauling Units (PU)
measures the electronegativity of a bond
Single Bond
An atomic bond between atoms that share one pair of electrons
C - C
Nonpolar Bond
A bond between 2 atoms of the same element that equally pull on the shared electron
Standard Temperature and Pressure (STP)
A temperature and pressure of 273 K and 1 atm
Limiting Reagent / Limiting Reactant
The first chemical to be used up in a chemical reaction
Dynamic Chemical Equilibrium
Equilibrium when a reversible reaction proceeds in both directions, so the net production is zero
Chemical Reaction
a reaction that forms a new substance by rearranging the atomic bonds between atoms. The process absorbs energy during bond-breaking and releases energy during bond-making.
HCl+NaOH→NaCl+H2O
Chemical Equilibrium
The state in which reactants and products are being formed at the same rate
Le Chatelier’s Principle
The statement that a reaction shifts to counteract a change in concentration or temperature of the reactants
If the pressure on a reaction at equilibrium is increased, then the reaction will shift to produce fewer moles of gas.
Conservation of Matter
Matter cannot be created or destroyed; it only changes form
chemical reaction
Reaction: Combination
2 elements or molecules combine to form 1 molecule
A+B -> AB C +O2 –> CO2
Excess Reagent / Excess Reactant
The leftover reagent(s) in a chemical reaction after the limiting reagent is depleted.
Endothermic
In an endothermic process, a substance gains thermal energy.
In an endothermic reaction, the reactants absorb heat while rearranging chemical bonds.
As ice melts into water, it absorbs heat from the environment
Exothermic
In an exothermic process, a substance releases thermal energy.
In an exothermic reaction, the reactants release heat while rearranging chemical bonds.
As water freezes into ice, it releases heat into the environment
Stoichiometry
uses a balanced chemical equation to determine the amount of reactants needed to create a certain amount of product or how much product can be created from a set amount of reactant
Reaction: Double Replacement
Elements in molecules replace each other
Reaction: Single Replacement
One element or molecule replaces another element in a molecule
Reaction: Decomposition
1 molecule is broken down into 2 separate elements or molecules
Pressure
the force exerted on an object over a given area
Reaction: Oxidation/Reduction (Redox)
Reaction in which electrons transfer, causing the oxidation number to change
Static Chemical Equilibrium
Equilibrium reached in an irreversible reaction that proceeds in one direction until all the reactants are used up
Oxidation Number
The charge on an atom
Activation Energy (Ea)
The amount of energy needed for a reaction to begin
Reaction: Neutralization
Reaction in which when an acid and base chemically react and form a salt and water with a resulting pH of 7
Reaction: Combustion
A compound containing carbon reacts with oxygen and burns releasing carbon dioxide
Chemical Equations
Notation that shows how 2 molecules or compounds react together to form a product
Gibbs Free Energy (ΔG)
The change in enthalpy minus the product of temperature and the change in entropy, measured in kJ per mol reaction
Spontaneity
Whether or not a process will proceed without an additional energy input;
ΔG<0
Solubility
the ability of a substance to be dissolved
Exothermic
In an exothermic process, a substance releases thermal energy.
In an exothermic reaction, the reactants release heat while rearranging chemical bonds.
As water freezes into ice, it releases heat into the environment
Solvent
a substance which dissolves other substances
if salt is dissolved in water, water is the solvent.
Calorimeter
A piece of equipment used to determine the heat change associated with a chemical reaction
Endothermic
In an endothermic process, a substance gains thermal energy.
In an endothermic reaction, the reactants absorb heat while rearranging chemical bonds.
As ice melts into water, it absorbs heat from the environment
Specific Heat (c)
The heat energy required to raise the temperature of a substance with a given mass by a given number of degrees.
Δheat=mcΔT
Standard Gibbs Free Energy of Formation (ΔGfo)
The change in energy that results from the formation of 1 mole of chemical from its component elements at 298 K
Enthalpy (H)
The quantity of heat in a system
Entropy (S)
A measure of the disorder of a system. The amount of thermal energy that cannot be used to do mechanical work as a system moves toward equilibrium.
Enthalpy of Solution / Enthalpy of Dissolution (ΔHsoln)
the heat that is absorbed or released when a solute dissolves into solution.
In an exothermic dissolution, the interactions between the solute particles are weaker than the interactions between solute and solvent particles. The ΔHsoln is negative.
In an endothermic dissolution, the interactions between solute particles are stronger than the interactions between solute and solvent particles. The ΔHsoln is positive.
Dissolution
The separation of an ionic compound into a cation and anion
Breaking apart of ionic NaCl salt crystal in water.
