Chemistry 112

Chemistry 112Chemistry 112

Overview of Chapters 1-4Overview of Chapters 1-4

Chapter 1 HighlightsChapter 1 Highlights

Chemistry is the study of matter, the physical substance of all materials.

The building blocks of matter are atoms, which combine to form compounds.

The different types of atoms are called elements, which are arranged systematically in the periodic table.

Chemistry is the study of matter, the physical substance of all materials.

The building blocks of matter are atoms, which combine to form compounds.

The different types of atoms are called elements, which are arranged systematically in the periodic table.

Atoms are composed of protons, neutrons, and electrons.

All atoms of the same element contain the same number of protons (and electrons) but may vary in the number of neutrons.

The protons and neutrons are found inside the tiny but dense nucleus, whereas the electrons are found in orbitals outside the nucleus.

Atoms are composed of protons, neutrons, and electrons.

All atoms of the same element contain the same number of protons (and electrons) but may vary in the number of neutrons.

The protons and neutrons are found inside the tiny but dense nucleus, whereas the electrons are found in orbitals outside the nucleus.

Chapter 1 Highlights (cont)


The arrangement of electrons in the orbitals is called the electronic configuration and determines the chemistry of an atom.

The arrangement of electrons in the orbitals is called the electronic configuration and determines the chemistry of an atom.



Types of Matter Types of Matter

States of MatterStates of Matter

Chemistry and Matter Physical Changes versus Chemical

Changes Physical changes involve changes in

appearance (i.e., changes in state such as melting).

Chemical changes result in new substances.

Chemistry and Matter Physical Changes versus Chemical

Changes Physical changes involve changes in

appearance (i.e., changes in state such as melting).

Chemical changes result in new substances.

The Building Blocks of Matter Atoms

Smallest representative units of the elements.

Compounds Different atoms linked together; e.g., H2O.

The Building Blocks of Matter Atoms

Smallest representative units of the elements.

Compounds Different atoms linked together; e.g., H2O.

The Building Blocks of Matter (cont) Dalton’s Atomic Theory

All matter is composed of indivisible atoms. All atoms of one element are identical to each

other but different than the atoms of other elements.

Compounds are formed when atoms of different elements combine in whole number ratios.

Atoms are rearranged during chemical reactions but atoms cannot be created or destroyed.

The Building Blocks of Matter (cont) Dalton’s Atomic Theory

All matter is composed of indivisible atoms. All atoms of one element are identical to each

other but different than the atoms of other elements.

Compounds are formed when atoms of different elements combine in whole number ratios.

Atoms are rearranged during chemical reactions but atoms cannot be created or destroyed.

The Periodic Table Used to organize the elements by

recurring chemical properties. Elements in the same vertical column of

the periodic table have similar chemical properties and are said to be in the same group or family.

The Periodic Table Used to organize the elements by

recurring chemical properties. Elements in the same vertical column of

the periodic table have similar chemical properties and are said to be in the same group or family.

The Periodic Table The Periodic Table

The Atom Components

Positive protons, negative electrons, and neutral neutrons

Atomic Number The number of protons in an atom,

which determines what element it is Mass Number

Number of protons + the number of neutrons

The Atom Components

Positive protons, negative electrons, and neutral neutrons

Atomic Number The number of protons in an atom,

which determines what element it is Mass Number

Number of protons + the number of neutrons

The Atom (cont) Isotopes

Isotopes of the same element have the same number of protons but differ in the number of neutrons.

Atomic Mass The atomic mass for each element

on the periodic table reflects the relative abundance of each isotope in nature.

The Atom (cont) Isotopes

Isotopes of the same element have the same number of protons but differ in the number of neutrons.

Atomic Mass The atomic mass for each element

on the periodic table reflects the relative abundance of each isotope in nature.

IsotopesIsotopes

Models of the Atom The Plum Pudding Model

Electrons are embedded in a sphere of positive charge.

The Nuclear Model All of the positive charge is in a tiny central

nucleus with electrons outside the nucleus. This model was developed by Rutherford

after his landmark experiment.

Models of the Atom The Plum Pudding Model

Electrons are embedded in a sphere of positive charge.

The Nuclear Model All of the positive charge is in a tiny central

nucleus with electrons outside the nucleus. This model was developed by Rutherford

after his landmark experiment.

The Rutherford Experiment

The Rutherford Experiment

Models of the Atom (continued) Bohr’s Solar System Model

Electrons circle the nucleus in orbits, which are also called energy levels.

An electron can “jump” from a lower energy level to a higher one upon absorbing energy, creating an excited state.

The concept of energy levels accounts for the emission of distinct wavelengths of electromagnetic radiation during flame tests.

Models of the Atom (continued) Bohr’s Solar System Model

Electrons circle the nucleus in orbits, which are also called energy levels.

An electron can “jump” from a lower energy level to a higher one upon absorbing energy, creating an excited state.

The concept of energy levels accounts for the emission of distinct wavelengths of electromagnetic radiation during flame tests.

The Solar System ModelThe Solar System Model

Electromagnetic RadiationElectromagnetic Radiation

Models of the Atom (continued) The Modern Model

Orbits are replaced with orbitals, volumes of space where the electrons can be found.

The arrangement of electrons in the orbitals is the electronic configuration of an atom, which determines the chemistry of an atom.

Models of the Atom (continued) The Modern Model

Orbits are replaced with orbitals, volumes of space where the electrons can be found.

The arrangement of electrons in the orbitals is the electronic configuration of an atom, which determines the chemistry of an atom.

The Orbital Model:Electronic Configurations

The Orbital Model:Electronic Configurations


Having eight valence electrons is particularly desirable (“the octet rule”).

Atoms form bonds with other atoms to satisfy the octet rule.

The two major types of chemical bonds are ionic and covalent.

Having eight valence electrons is particularly desirable (“the octet rule”).

Atoms form bonds with other atoms to satisfy the octet rule.

The two major types of chemical bonds are ionic and covalent.

Electronegativity is the ability to attract shared electrons.

The type of bond formed between two atoms depends on their difference in electronegativity.

Ionic bonds form between atoms with a large difference in electronegativity (generally a metal and a nonmetal).

Electronegativity is the ability to attract shared electrons.

The type of bond formed between two atoms depends on their difference in electronegativity.

Ionic bonds form between atoms with a large difference in electronegativity (generally a metal and a nonmetal).



Nonpolar covalent bonds form between atoms with little difference in electronegativity (generally two nonmetals).

Polar covalent bonds form between atoms with intermediate difference in electronegativity.

There are many ways to depict molecules.

Nonpolar covalent bonds form between atoms with little difference in electronegativity (generally two nonmetals).

Polar covalent bonds form between atoms with intermediate difference in electronegativity.

There are many ways to depict molecules.



The Octet Rule Atoms with eight valence electrons

are particularly stable, an observation called the octet rule.

Atoms form bonds with other atoms to achieve a valence octet.

The Octet Rule Atoms with eight valence electrons

are particularly stable, an observation called the octet rule.

Atoms form bonds with other atoms to achieve a valence octet.

ElectronicConfiguration of Noble

Gases

ElectronicConfiguration of Noble

Gases

Types of Compounds Types of Compounds

Lewis Dot StructuresLewis Dot Structures

Ionic Bonds Ionic compounds result from the loss

of electrons by one atom (usually a metal) and the gain of electrons by another atom (usually a nonmetal).

Ionic bonds arise from the attraction between particles with opposite charges (electrostatic forces); e.g., Na+ Cl-.

Ionic Bonds Ionic compounds result from the loss

of electrons by one atom (usually a metal) and the gain of electrons by another atom (usually a nonmetal).

Ionic bonds arise from the attraction between particles with opposite charges (electrostatic forces); e.g., Na+ Cl-.

Ionic CompoundsIonic Compounds

Covalent Bonds Covalent bonds are formed when

two atoms share one or more electron pairs.

When two atoms share one pair of electrons, the result is a single bond.

Two shared pairs of electrons is a double bond; three is a triple bond.

Covalent Bonds Covalent bonds are formed when

two atoms share one or more electron pairs.

When two atoms share one pair of electrons, the result is a single bond.

Two shared pairs of electrons is a double bond; three is a triple bond.

Equal Sharing versus Unequal Sharing When two different kinds of atoms are

bonded, the electrons are usually shared unequally.

When a bond exists between two identical kinds of atoms, the electrons are shared equally.

An atom with greater electronegativity has a greater ability to attract shared electrons.

Equal Sharing versus Unequal Sharing When two different kinds of atoms are

bonded, the electrons are usually shared unequally.

When a bond exists between two identical kinds of atoms, the electrons are shared equally.

An atom with greater electronegativity has a greater ability to attract shared electrons.

ElectronegativityElectronegativity

Polar vs. Nonpolar BondsPolar vs. Nonpolar Bonds

Representing Structures In a structural formula, atoms are

represented by chemical symbols, and bonds are represented by lines.

In a line drawing, any point where lines connect or terminate is understood to be a carbon atom with sufficient bonded hydrogen atoms to achieve the four bonds necessary for carbon.

Representing Structures In a structural formula, atoms are

represented by chemical symbols, and bonds are represented by lines.

In a line drawing, any point where lines connect or terminate is understood to be a carbon atom with sufficient bonded hydrogen atoms to achieve the four bonds necessary for carbon.

Drawing MoleculesDrawing Molecules


Reaction equations have with the initial materials (reactants) on the left, followed by a reaction arrow pointing from left to right, and the final materials (products) on the right.

A balanced equation has the same number and kinds of atoms on both sides of the equation.

Reaction equations have with the initial materials (reactants) on the left, followed by a reaction arrow pointing from left to right, and the final materials (products) on the right.

A balanced equation has the same number and kinds of atoms on both sides of the equation.

The relationship between the amounts of reactants and products is the stoichiometry, which comes from a balanced reaction equation.

The SI unit for measuring atoms and molecules is the mole.

In an oxidation-reduction reaction, electrons are transferred from one material (the substance that is oxidized) to another material (the substance that is reduced).

The relationship between the amounts of reactants and products is the stoichiometry, which comes from a balanced reaction equation.

The SI unit for measuring atoms and molecules is the mole.

In an oxidation-reduction reaction, electrons are transferred from one material (the substance that is oxidized) to another material (the substance that is reduced).


Balanced Reaction Equations Writing a Chemical Reaction

The starting materials, the reactants, are written on the left.

The materials that are produced, the products, are written on the right.

Reactants are separated from products by a horizontal arrow pointing from left to right.

Balanced Reaction Equations Writing a Chemical Reaction

The starting materials, the reactants, are written on the left.

The materials that are produced, the products, are written on the right.

Reactants are separated from products by a horizontal arrow pointing from left to right. Na + Cl NaCl

Reactants Product

Balanced Reaction Equations (cont) Balancing the Equation

The law of conservation of matter states that matter can neither be created nor destroyed in a chemical reaction.

The number and kind of atoms on the left-hand side of an equation must be equal to the number and kind of atoms on the right.

Balanced Reaction Equations (cont) Balancing the Equation

The law of conservation of matter states that matter can neither be created nor destroyed in a chemical reaction.

The number and kind of atoms on the left-hand side of an equation must be equal to the number and kind of atoms on the right.H2 + O2 H2O Incorrect

2 H2 + O2 2 H2O Correct

Balanced Reaction Equations (cont) Stoichiometry

The stoichiometry of a chemical reaction is the relationship between the number of molecules of the reactants and products in the balanced reaction equation.

A reactant present in insufficient amounts is the limiting reagent.

Balanced Reaction Equations (cont) Stoichiometry

The stoichiometry of a chemical reaction is the relationship between the number of molecules of the reactants and products in the balanced reaction equation.

A reactant present in insufficient amounts is the limiting reagent.

The Mole The mole is the SI unit of measure to

describe the amount of matter that is present.

One mole is equal to 6.02 x 1023 particles (Avogadro’s number).

One mole of an element has a mass that is equal to the atomic mass of that element in grams.

One mole of a compound has a mass that is equal to the molecular/formula mass of that compound in grams.

The Mole The mole is the SI unit of measure to

describe the amount of matter that is present.

One mole is equal to 6.02 x 1023 particles (Avogadro’s number).

One mole of an element has a mass that is equal to the atomic mass of that element in grams.

One mole of a compound has a mass that is equal to the molecular/formula mass of that compound in grams.

The Mole The Mole

Stoichiometry Calculations The units of molar mass are

grams/mole. Moles x molar mass = mass.

Example: 2.0 mol CO2 x 44 g/mol = 88 g CO2

Mass/molar mass= moles. Example: 132 g CO2 / 44 g/mol = 3.0 mol CO2

Stoichiometry Calculations The units of molar mass are

grams/mole. Moles x molar mass = mass.

Example: 2.0 mol CO2 x 44 g/mol = 88 g CO2

Mass/molar mass= moles. Example: 132 g CO2 / 44 g/mol = 3.0 mol CO2

Stoichiometry Calculations The expected mass of a product or

reactant can be calculated for any reaction by using the balanced equation and the molar mass.

Stoichiometry Calculations The expected mass of a product or

reactant can be calculated for any reaction by using the balanced equation and the molar mass.

Oxidation-Reduction Reactions Defined

Oxidation-reduction (“redox”) reactions involve the transfer of electrons from one substance to another.

Oxidized substances lose electrons and reduced substances gain electrons.

Oxidation-Reduction Reactions Defined

Oxidation-reduction (“redox”) reactions involve the transfer of electrons from one substance to another.

Oxidized substances lose electrons and reduced substances gain electrons.

Oxidation-ReductionOxidation-Reduction

Oxidation-Reduction Reactions (cont) The Chemistry of Batteries

Combining a readily oxidized substance with an easily reduced substance can create a battery.

The oxidized material is the anode and the reduced material is the cathode of the battery.

Oxidation-Reduction Reactions (cont) The Chemistry of Batteries

Combining a readily oxidized substance with an easily reduced substance can create a battery.

The oxidized material is the anode and the reduced material is the cathode of the battery.

BatteriesBatteries


Intermolecular forces hold the molecules of a material together.

Stronger intermolecular forces lead to higher melting and boiling temperatures.

The relative strengths of intermolecular forces generally follow the trend:

hydrogen bonds > dipole-dipole interactions > London forces

Intermolecular forces hold the molecules of a material together.

Stronger intermolecular forces lead to higher melting and boiling temperatures.

The relative strengths of intermolecular forces generally follow the trend:

hydrogen bonds > dipole-dipole interactions > London forces

Like dissolves like. That is, polar solutes dissolve in polar solvents.

Acids are proton (H+) donors; bases are proton acceptors that produce OH- in solution.

The pH measures the acidity of a solution: pH < 7.0 is acidic; pH > 7.0 is basic; pH = 7.0 is neutral.

Acids react with bases in neutralization reactions.

Like dissolves like. That is, polar solutes dissolve in polar solvents.

Acids are proton (H+) donors; bases are proton acceptors that produce OH- in solution.

The pH measures the acidity of a solution: pH < 7.0 is acidic; pH > 7.0 is basic; pH = 7.0 is neutral.

Acids react with bases in neutralization reactions.



States of Matter Review of Types of Bonds

1.Chemical bonds (intramolecular forces) hold atoms together.

2.The three types of chemical bonds are ionic, polar covalent, and nonpolar covalent.

3.Intermolecular forces hold molecules together.

States of Matter Review of Types of Bonds

1.Chemical bonds (intramolecular forces) hold atoms together.

2.The three types of chemical bonds are ionic, polar covalent, and nonpolar covalent.

3.Intermolecular forces hold molecules together.

Review of Types of BondsReview of Types of Bonds

Chapter OutlineChapter Outline

States of Matter (cont) Particle Cohesion Determines Physical

State In general, the relative strengths of

intermolecular forces follows the trend: gases < liquids < solids

Changes of State Adding energy breaks intermolecular forces

and causes molecules to change their state. The stronger the intermolecular forces of a

compound, the higher are the melting and boiling points.

States of Matter (cont) Particle Cohesion Determines Physical

State In general, the relative strengths of

intermolecular forces follows the trend: gases < liquids < solids

Changes of State Adding energy breaks intermolecular forces

and causes molecules to change their state. The stronger the intermolecular forces of a

compound, the higher are the melting and boiling points.

Changes of StateChanges of State

Types of Intermolecular Forces within Pure Substances London dispersion forces

A temporary dipole in one molecule can induce a dipole in a neighboring molecule.

The negative end of one temporary dipole can attract the positive end of an induced dipole; these attractions are called London dispersion forces.

London forces tend to be fairly weak.

Types of Intermolecular Forces within Pure Substances London dispersion forces

A temporary dipole in one molecule can induce a dipole in a neighboring molecule.

The negative end of one temporary dipole can attract the positive end of an induced dipole; these attractions are called London dispersion forces.

London forces tend to be fairly weak.

London Dispersion Forces London Dispersion Forces

Types of Intermolecular Forces within Pure Substances (cont) Dipole-dipole interactions

Dipole-dipole interactions exist between molecules with polar covalent bonds.

Dipole-dipole interactions are typically stronger than London dispersion forces.

Types of Intermolecular Forces within Pure Substances (cont) Dipole-dipole interactions

Dipole-dipole interactions exist between molecules with polar covalent bonds.

Dipole-dipole interactions are typically stronger than London dispersion forces.

Dipole-Dipole Interactions Dipole-Dipole Interactions

Types of Intermolecular Forces within Pure Substances (cont) Hydrogen Bonds

Hydrogen bonds are a special type of dipole-dipole interaction.

Hydrogen bonds can occur when H is bonded to one of the highly electronegative atoms N, O, or F. An example is H2O.

Hydrogen bonds are typically quite strong.

Types of Intermolecular Forces within Pure Substances (cont) Hydrogen Bonds

Hydrogen bonds are a special type of dipole-dipole interaction.

Hydrogen bonds can occur when H is bonded to one of the highly electronegative atoms N, O, or F. An example is H2O.

Hydrogen bonds are typically quite strong.

Hydrogen Bonds in WaterHydrogen Bonds in Water

MixturesMixtures

Forming Solutions Like dissolves like

Ionic solutes often dissolve in polar solvents;e.g., NaCl dissolves in H2O.

Polar solutes generally dissolve in polar solvents; e.g., NH3 in H2O.

Nonpolar solutes generally do not dissolve well in polar solvents; e.g., oil in H2O.

Forming Solutions Like dissolves like

Ionic solutes often dissolve in polar solvents;e.g., NaCl dissolves in H2O.

Polar solutes generally dissolve in polar solvents; e.g., NH3 in H2O.

Nonpolar solutes generally do not dissolve well in polar solvents; e.g., oil in H2O.

NaCl Dissolving in H2ONaCl Dissolving in H2O

Emulsions Emulsifying agents are molecules that

contain a polar portion and a nonpolar region.

Soap is an example of an emulsifying agent that can form a suspension of a nonpolar material in a polar solvent (an “emulsion”).

Emulsions Emulsifying agents are molecules that

contain a polar portion and a nonpolar region.

Soap is an example of an emulsifying agent that can form a suspension of a nonpolar material in a polar solvent (an “emulsion”).

Emulsification with SoapEmulsification with Soap

Measuring Amounts in Solution Solubility

The maximum amount of a solute that dissolves in a solvent

Molarity The amount of a solute dissolved in a

solvent is its concentration. Concentration is often measured in

moles/liter, also called molarity (M).

Measuring Amounts in Solution Solubility

The maximum amount of a solute that dissolves in a solvent

Molarity The amount of a solute dissolved in a

solvent is its concentration. Concentration is often measured in

moles/liter, also called molarity (M).

Acid-Base Chemistry Definitions of Acids and Bases

Acids turn litmus paper red; bases turn litmus paper blue.

Acids produce H+ in solution; bases produce OH- in solution.

Acids are proton donors; bases are proton acceptors.

Acid-Base Chemistry Definitions of Acids and Bases

Acids turn litmus paper red; bases turn litmus paper blue.

Acids produce H+ in solution; bases produce OH- in solution.

Acids are proton donors; bases are proton acceptors.

Acid-Base Chemistry (cont) The pH Scale: a measure of acidity

Acid-Base Chemistry (cont) The pH Scale: a measure of acidity

Acid-Base Chemistry (cont) Acid-Base Indicators

Molecular sensors of H+.

Acid-Base Chemistry (cont) Acid-Base Indicators

Molecular sensors of H+.

H+

Acid-Base Chemistry (cont) Neutralization Reactions: equal molar

amounts of an acid and a base react to form a neutral solution.

Acid-Base Chemistry (cont) Neutralization Reactions: equal molar

amounts of an acid and a base react to form a neutral solution.

HCl + NaOH NaCl + H2O

Acid-Base Chemistry (cont) Buffers: contain a weak acid and its

conjugate base, which react with added H+ or OH- to prevent pH changes.

Acid-Base Chemistry (cont) Buffers: contain a weak acid and its

conjugate base, which react with added H+ or OH- to prevent pH changes.

HA H+ + A-

Adding acid: H+ reacts with A- to make more HA

Adding base: OH- reacts with HA to make more A- and H2O

Chemistry 112

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Transcript of Chemistry 112