Atoms Moles Formular And Equation Flashcards
Atom
The smallest particle of an element that can take part in a chemical reaction. OR The smallest part of an element that can ever exist and still possess the chemical properties of that element.
Molecule
A group of atoms bonded together. Can be made of atoms of the same or different elements.
Ion
An atom or group of atoms which possesses an electric charge.
Cation
Positively charged ion.
Anion
Negatively charged ion.
Chemical Formula
Representation of a molecule using symbols of its component elements.
Relative Atomic Mass
The number of times the average mass of one atom of that element is heavier than one-twelfth the mass of one atom of carbon-12.
Relative Molecular Mass
The number of times the average mass of one molecule of it is heavier than one-twelfth the mass of one atom of carbon-12. OR the sum of the relative atomic masses of all the atoms in one molecule of that substance.
Mole
The amount of a substance containing as many elementary entities as the number of atoms in exactly 12 grams of carbon-12.
Avogadro Number
6.02 x 10^23
Molar Mass
The mass of one mole of a substance expressed in grams.
Empirical Formula
The simplest formula of a compound, showing the ratio in which elements are combined.
Molecular Formula
The exact number of moles of atoms of the component elements in one mole of the compound.
Law of Conservation of Mass
Matter is neither created nor destroyed during a chemical reaction but changes from one form to another.
Law of Definite Proportions
All pure samples of a particular chemical compound contain similar elements combined in the same proportion by mass.
Law of Multiple Proportions
If two elements, A and B, combine to form more than one chemical compound, then the various masses of one element, A, which combine separately with a fixed mass of the other element, B, are in simple multiple ratio.
Valency
The number of hydrogen atoms that can combine with or replace (either directly or indirectly) one atom of that element.
Atomicity
“The number of atoms in each molecule of an element.”
Diatomic
“A molecule consisting of two atoms.”
Monatomic
“Molecules that can exist independently as single atoms.”
Polyatomic
“Molecules consisting of more than two atoms.”
Radical
“A group of atoms that acts as a single unit in a molecular formula (e.g., trioxonitrate(V), -NO3, hydroxide, -OH, trioxocarbonate(IV), -CO3, ammonium - NH4).”
Isotope
“Atoms of the same element that exist in more than one form and have different masses.”
Atomic Mass Unit (amu)
“An amount of matter that has a mass one-twelfth that of carbon-12.”
Formula Mass
“A more general term for relative molecular mass, referring not only to molecules but also ions, radicals, electrons, or other specified groups or nuclear particles.”
Molar Mass Unit
“grams per mole (g mol^-1)”
Percentage Mass of an Element in a Compound
The mass of 1 mole of the element divided by the mass of 1 mole of the compound, multiplied by 100%.
Reacting Mass
“The percentage by mass of an element also represents its reacting mass in forming that compound.”
Laws of Chemical Combination
“Four laws (Law of Conservation of Mass, Law of Definite Proportions, Law of Multiple Proportions, Law of Reciprocal Proportions) that describe the general features of a chemical change.”
Law of Reciprocal Proportions
“The masses of several elements, A, B, C, which combine separately with a fixed mass of another element, D, are the same as, or simple multiples of, the masses in which A, B, C, themselves combine with one another.”
Element Symbol
A one- or two-letter abbreviation for an element’s name (e.g., H for hydrogen, Ca for calcium).
Chemical Equation
A representation of a chemical reaction using chemical formulas.
Reactant
A substance that takes part in and undergoes change during a reaction.
Product
A substance produced during a chemical reaction.
Coefficient
A number placed in front of a chemical formula in a chemical equation to indicate the relative number of moles of that substance involved in the reaction.
Subscript
A number written as a subscript after the symbol of an element in a chemical formula to indicate the number of atoms of that element in one molecule of the substance.
Balanced Equation
A chemical equation in which the number of atoms of each element is the same on both the reactant and product sides.
State Symbols
Symbols used in chemical equations to indicate the physical state of a substance: (s) for solid, (l) for liquid, (g) for gas, (aq) for aqueous (dissolved in water).
Relative Formula Mass
The sum of the relative atomic masses of the atoms in the formula of a substance.
Stoichiometry
The study of the quantitative relationships or ratios between amounts of reactants and products.
Limiting Reactant
The reactant that is completely consumed in a chemical reaction and determines the amount of product formed.
Excess Reactant
The reactant that is present in a greater quantity than necessary to react completely with the limiting reactant.
Theoretical Yield
The maximum amount of product that can be formed from a given amount of limiting reactant.
Actual Yield
The amount of product actually obtained from a chemical reaction.
Percentage Yield
(Actual Yield / Theoretical Yield) x 100%
Oxidation Number
The valency of an element; a number (positive or negative) given to an element to indicate its combining power.
Balancing Equations
The process of adjusting the coefficients in a chemical equation to ensure that the number of atoms of each element is the same on both sides of the equation, thus obeying the Law of Conservation of Mass.
Mole Ratio
The ratio between the amounts in moles of any two substances in a balanced chemical equation.
Stoichiometric Calculation
Using mole ratios from balanced chemical equations to calculate the amounts of reactants and products involved in a chemical reaction.
Molar Volume of a Gas
The volume occupied by one mole of a gas at a specified temperature and pressure (standard temperature and pressure (STP)).
Standard Temperature and Pressure (STP)
0 degrees Celsius (273.15 K) and 1 atmosphere (atm) pressure.
Concentration
The amount of solute present in a given amount of solvent or solution.
Solute
A substance that is dissolved in a solution.
Solvent
A substance that dissolves a solute to form a solution.
Aqueous Solution
A solution in which the solvent is water.
Molarity (M)
A unit of concentration defined as the number of moles of solute per liter of solution (mol/L).
Titration
A laboratory procedure used to determine the concentration of a solution by reacting it with another solution of known concentration.
Standard Solution
A solution of accurately known concentration.
End Point
The point in a titration at which the indicator changes color, signaling that the reaction is complete.
Indicator
A substance that changes color depending on the pH of the solution, used to detect the end point of a titration.
Spectator Ion
An ion that exists in the same form on both the reactant and product sides of a chemical equation; it does not participate in the reaction.
Net Ionic Equation
A chemical equation that shows only the ions and molecules directly involved in a chemical reaction, excluding spectator ions.
Precipitate
A solid that forms out of solution during a chemical reaction.
Acid
A substance that donates protons (H+ ions) or accepts electrons.
Base
A substance that accepts protons (H+ ions) or donates electrons.
Neutralization Reaction
A reaction between an acid and a base, typically producing water and a salt.
Salt
An ionic compound formed from the reaction of an acid and a base.
pH
A measure of the concentration of hydrogen ions (H+) in a solution; a scale used to specify the acidity or basicity of an aqueous solution.
Strong Acid/Base
An acid or base that completely ionizes (dissociates) in solution.
Weak Acid/Base
An acid or base that only partially ionizes in solution.
Buffer Solution
A solution that resists changes in pH when small amounts of acid or base are added.
Redox Reaction
A chemical reaction that involves the transfer of electrons between reactants, resulting in changes in oxidation states.
Oxidation
A process involving the loss of electrons or an increase in oxidation number.
Reduction
A process involving the gain of electrons or a decrease in oxidation number.
Oxidizing Agent
A substance that causes oxidation by accepting electrons; it gets reduced in the process.
Reducing Agent
A substance that causes reduction by donating electrons; it gets oxidized in the process.
