Chemistry Chemistry is ultimately the study of matter including how it behaves and . Additionally in this unit we talked about how to describe properties and changes using diagrams and nomenclature, and equations.

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What is a Chemical Reaction? A process where two or more substances react to produce a new substance with new properties

Chemistry Chemistry is ultimately the study of matter including how it behaves and . Additionally in this unit we talked about how to describe properties and changes using diagrams and nomenclature, and equations.

Types of chemical reactions

Combustion When hydrocarbon reacts with oxygen causing it to “burn”; there are two types of combustion which are sorted based on the amount of oxygen present

Incomplete Combustion A reaction in which limited oxygen is present which produces water, carbon dioxide, soot (C(s)), carbon monoxide, and water vapor

Complete Combustion Adequate or excess oxygen is present in reaction and it yields carbon dioxide and water vapor

Decomposition A (complex) compound breaks down into 2 or more (simpler) products

Synthesis 2 or more reactants combining to form one [complexer] product

Single Displacement One metal OR one non-metal(in it's elemental state) displaces\switches spots with another metal OR non-metal which is a part of a compound

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Neutralization A special type of double displacement reaction that involves an acid and a base reacting which yields water and an ionic compound/salt

pH Scale

Acidic A substance is considered acidic if it has a pH level of less than 7; the lower the pH level the more acidic a substance is

Basic A solution is considered basic when it has a pH level of 8 or higher

Neutral A solution with equal concentration of hydronium and hydroxide ions (with a pH level of 7)

pH scale It's a going from 1-14 scale used to compare the acidity of solutions

*Note a pH scale is logarthmic meaning one substance is 10x more acidic as the one before (from 14-1) (e.g Lemon juice is 1000x more acidic than coffee)

pH A measure of how acidic or basic a solution which is based off the concentration of hydroxide ions and hydronium ions released when the substance is dissolved in water

If there is a higher concentration of hydroxide the solution is basic and if there's a higher concentration on hydronium ion (H+) the solution is acidic

Acids & Bases For a compound to be considered an acid or base it must be in a aqueous state (Aqueous(aq) it means the compound is dissolved in water )

Acids An acid is a compound that produces a hydrogen ion (specifically the hydronium ion H+) when aqueous (released into water) therefore all acids have hydrogen as they need hydrogen to produce the ion

Properties of Acids: -Has pH of less than 7 -Tastes sour -Good conductor -Strong acids are highly corrosive -Release hydonium ions when dissolved in water

Types of Acids

Oxyacids Oxyacids must contain oxygen, hydrogen and another element

Binary Acids Binary Acids are composed of hydrogen and one other element typically a non-metal

Base Bases are compounds which produce a hydroxide ion when aqueous (disolved in water) and are usually composed of hydroxide (OH) and a metal

Properties of a Base: -Has pH of more tthan 7 -Tastes bitter -Good conductor -Strong bases are highy corrosive -Release hydroxide ions when dissoved in water

Octet Rule Atoms are always trying to stabilize by filling their valence shell by attaining 8 electrons (except hydrogen, helium, and lithium which only need two electrons) by getting or losing electrons. Elements (not including transitional metals) in main groups 1-3 lose electrons and 5-7 gain electrons (some groups lose electrons as it requires less energy to acheive stability that way)

Ions Ions are charged atoms; atoms try to have a full outer orbital therefore when they gain or lose electrons which causes an imbalance of protons and electrons thus losing its neutral state, forming ions (Image to Left:Lewis Dot Diagrams for Ions)

Anion Negatively charged ions meaning there are more electrons than protons (typically nonmetals)

Cations Positively charged ions meaning they have more protons than electron (and are typically metals)

Compounds A compound is a substance formed of 2 or more elements in a SPECIFIC ratio

Types of Compounds

Ionic Compound Any compound composed of a metal and non-metal (cation + anion). Essentially,“excess” electrons on the valence shell preventing a cation from being stable is transferred to anions to allow both atoms to have a stable octet and create an ionic bond (Image to left: Lewis Dot Structures for potassium oxide)

Molecular/Covalant Compounds Molecular compounds are compounds formed of 2 or more non-metals which share valence electrons (and there energy) to attain a stable octet thus creating a covalent bond

Polyatomic Ions An ion which is formed from two or more atoms but act like a single particles (therefore in a compound the polyatomic acts like a non-metal (except ammonium) in an compound however you do not add -ide to the end)

Diagrams

Lewis Dot Diagrams/Structures A diagram where the chemical symbol representing the atom is written in the middle and dots are drawn around the symbol to represent the number of valence electrons (which be used to show the energy level and bondings of an atom or a compound) *More Lewis Dot Diagrams are situated under ions, iomic compounds, and molecular compounds

Bohr-Rutheford Diagrams *Not usesd as much as Lewis diagrams to show bondings or elements after calcium (#20) as it can get very crowded/messy

Physical & Chemical Properties & Changes

Properties Essentially, observations which can be used to identify a substance

Chemical Property A characteristic which describes the way a given substance interacts with anther substance

Examples -Combustibility -Reactivity -Acidity

Physical Property A characteristic which can be observed without causing a chemical reaction and can typically be observed with your senses

Examples -Odor -Texture -Viscosity -Ductility -Boiling/melting point

Types of Changes

Chemical Change An irreversible or difficult to reverse change that alters the chemical composition of a given substance which is evident as new substances and/or properties are formed (ex oxidizatin of iron)

Indicators of Chemical Change -Bubbles are present indicating a new gas is formed -Change in color -A solid is formed by 2 liquids called a percipitate -Heat and/or light is absorbed or produced

Physical Change An easily reversible change in which ONLY the state and/or appearance changes and chemical composition remains unchanged (ex. Liquid water freezing to become ice)

Describing Chemical Reactions Reactants =Substances on the left-side of the arrow you start the reaction with Products=Substances on the right-side of the arrow which are the chemicals produced during the reaction

Word Equation Describes chemical reactions using the full names of reactants and products

Chemical Equations Chemical symbols/formulas are used to describe chemicals (reactants and products) involved in the reaction (an abreveation of the state may also be included in the subscipt)

Skeleton Chemical Equation Chemical symbols/formulas are used to describe chemicals (reactants and products) involved in the reaction (an abreveation of the state may also be included in the subscipt) *Refer to image under main idea

Balanced Chemical Equations A specific type of chemical equation where, both sides of the arrow must have the same amount of each type of atom and in order to acheive that one must use coeffcients (tchart method is commonly used to balance equations as seen )

Law of Conservation of Mass The total mass of the reactants in a chemical reaction will always equal the product as matter (atoms) can't be created or destroyed meaning they are conserved and rearranged only

Nomenclature (Naming Chemical Compounds)

Naming Bases Naming process is similar to ionic compounds as bases are oftens a cation (metal) plus hydroxide which is an anion

Formula->Name As bases are often ionic compounds, you would first write the name of the appropriate metal then you would write hydroxide (it's important to indicate the compound is aqueous or else it's not a base)

Name->Formula Identify the metal and the hydroxide ion (as the non-metal) then write down their chemical symbols and find their charges and apply crossover method (similar to ionic compounds) and in the subscript include "aq" in brackets to indicate the compound is a base

Naming Acids

Naming Binary acids

Naming Oxyacids Similar to binary acids, however you omit the "hydro" and begin with the root word of the element (which is not hydrogen or oxygen) and add "ic" then write acid

*Note Oxyacids are formed of polyatomic ions which have multiple derivatives and each deravitive has it's own ending "ic" is for acids with the base polyatomic ion Base + one oxygen (has prefix and suffix per...ic) Base - one oxygen (ending is -ous) Base - 2 oxygen (hypo...ous) *in place of dots place the root of the non-oxygen element

Naming Ionic Compounds

Name -> Formula Write chemical symbols for elements then ionic charges (from P.T) on top and crossover the charge numbers so they become the subscript and simplify these numbers if necessary

Formula -> Name Write metal name + non-metal root + “-ide” gives chemical name *Note for multivalent elements you must determine the charge by using the process below and checking if both mean the same

Naming Covalent/Molecular Compounds

Name -> Formula Molecular compounds have prefixes indicating how many of each atom they have and the root tells you the name of the elements used; find the corresponding symbols used to form the compound and apply subscript according to prefix (*Note you DO NOT crossover the charges or subscripts)

Formula -> Name Write appropriate prefix of first element using subscript then chemical name as one word then repeat steps from above for 2nd element & add "ide" to the end

Naming Polyatomic Ions

Naming Ionic Compounds with Polyatomic Ions In ionic compounds, polyatomic ions are used like non-metals and are the anions of the compound since they are negatively charged (except ammonium ion NH₄+)

There can be many derivatives of polyatomic ion however there is a base polyatomic ion {refer to chemistry reference sheet} (ending for base is ...ate) Base + one oxygen (has prefix and suffix per...ate) Base - one oxygen (ending is -ite) Base - 2 oxygen (hypo...ite) *in place of dots place the root of the non-oxygen element