Chapter 2 Chemistry. Chemistry Matter anything that has mass & takes up space Matter anything that has mass & takes up space Mass amount of matter.

Chapter 2 ChemistryChapter 2 Chemistry

ChemistryChemistry

• Matter Matter anything that has mass & anything that has mass & takes up spacetakes up space

• MassMass amount of matter an object amount of matter an object hashas

• ElementsElements pure substances that pure substances that cannot cannot be broken down into be broken down into simpler simpler kinds of matterkinds of matter

• Important elements : Important elements : C, O, H, NC, O, H, N

ChemistryChemistry

• Atom Atom simplest particle of an element simplest particle of an element the properties of an atom the properties of an atom

determine the properties determine the properties of of that matterthat matter

• Nucleus Nucleus core of an atom ; protons & core of an atom ; protons & neutronsneutrons

1.1. Protons Protons + charge , mass 1 amu + charge , mass 1 amu2.2. Electrons Electrons - charge, no mass - charge, no mass3.3. NeutronsNeutrons no charge, mass 1 amu no charge, mass 1 amu

Electrons outside the nucleus on shells

2 on the first & 8 on the rest

Periodic TablePeriodic Table• Arranged in increasing atomic #Arranged in increasing atomic #

• Atomic # = number of protonsAtomic # = number of protons

• # of Protons = number of electrons# of Protons = number of electrons

• Atomic mass = # of protons + # of Atomic mass = # of protons + # of neutronsneutrons

• Each column has the same number Each column has the same number of outside ( valence electrons)of outside ( valence electrons)

ChemistryChemistry

• Compound Compound pure substance of 2 or pure substance of 2 or more more elements elements combinedcombined

HH22O, CHO, CH44, (NH, (NH44))22SOSO4 4

BondsBonds• Bonds Bonds attachments of attachments of

atoms atoms in a compoundin a compound

1.1.Covalent Covalent electrons shared electrons shared

2.2. Ionic Ionic 1 atom gains 1 atom gains electrons & 1 atom loseselectrons & 1 atom loses

1111

ChemistryChemistry• Molecule Molecule simplest part of a simplest part of a

substance substance that has all the that has all the properties of properties of that substance that substance and can exist and can exist by itselfby itself

can be two atoms of the can be two atoms of the same same element or more element or more than one than one type of elementtype of element

• Ex: OEx: O22, N, N22, C, C66HH1212OO66

ChemistryChemistry

• Reaction Reaction two substances interact & two substances interact & change identitychange identity

Reactants ------Reactants ------ Products Products

HH22 + O + O22 → 2H→ 2H22OO

↔↔ Means that the reaction Means that the reaction

can go can go both waysboth ways

Chemistry Chemistry

• ExothermicExothermic reactions that release reactions that release heat/ heat/ energyenergy

• Endothermic Endothermic reactions that absorb reactions that absorb heat/energyheat/energy

• Activation energy Activation energy energy needed energy needed to to start a reactionstart a reaction

ChemistryChemistry

• Catalyst Catalyst speed up reactions by speed up reactions by lowering lowering activation activation energyenergy

• Enzymes Enzymes are biological catalysts are biological catalysts

• Substrate substance that binds to Substrate substance that binds to enzymesenzymes

EnzymesEnzymes

FunctionsFunctions

• Are substrate specificAre substrate specific

• Lock & key fitLock & key fit

• Speed up reactions by Speed up reactions by lowering activation lowering activation energyenergy

ChemistryChemistry

• Solutions Solutions are mixture where one are mixture where one substance is dissolved in substance is dissolved in

anotheranother• Solute Solute substance that gets dissolved substance that gets dissolved

Ex: Kool Aid PowderEx: Kool Aid Powder• Solvent Solvent does the dissolving does the dissolving

Ex: Water – water is the Ex: Water – water is the universal universal solventsolvent

ChemistryChemistry

• Concentration Concentration amount of solute per amount of solute per amount amount of solutionof solution

tells us how spread out the tells us how spread out the particles areparticles are

• Saturated Saturated no more solute can be added no more solute can be added

it has the maximum amount of it has the maximum amount of solutesolute

• Aqueous Aqueous something is dissolved in water something is dissolved in water (aq) (aq)

ChemistryChemistry

• Dissociation of water Dissociation of water

HH22O ↔ HO ↔ H++ + OH + OH--

hydrogen ion + hydroxide hydrogen ion + hydroxide ionion

• Ions Ions are any particle that has a are any particle that has a chargecharge

ChemistryChemistry

• ACIDS & BASESACIDS & BASES

• Acids Acids form hydrogen ions in solution (H+ ) form hydrogen ions in solution (H+ )

have a sour tastehave a sour taste

Ex: HCl Ex: HCl H H++ + Cl + Cl--

• Bases Bases form hydroxide ions in solution form hydroxide ions in solution (OH-)(OH-)

have a bitter tastehave a bitter taste

Ex: NaOH Ex: NaOH Na Na++ + OH + OH ––

ChemistryChemistry

• pH Scale pH Scale measures the concentration of measures the concentration of hydrogen ions in solutionhydrogen ions in solution

Range is 0-14Range is 0-14 0 – 7 is an acid0 – 7 is an acid 7- 14 is basic (alkaline)7- 14 is basic (alkaline)→ → 7 is neutral (water)7 is neutral (water)

• Buffer Buffer substances that neutralize a substances that neutralize a small amount of acid or base.small amount of acid or base.

maintain the pH within our bodies.maintain the pH within our bodies.