Presentation on theme: "Chapter 2 Chemistry of Life"— Presentation transcript:
1 Chapter 2 Chemistry of Life Modern Biology TextbookHolt
2 Objectives Chapter 2 Define the term matter. Section 1 Composition of MatterChapter 2ObjectivesDefine the term matter.Explain the relationship between elements and atoms.Draw and label a model of the structure of an atom.Explain how compounds affect an atom’s stability.Contrast covalent and ionic bonds.
3 Matter Chapter 2 Matter is anything that occupies space and has mass. Section 1 Composition of MatterChapter 2MatterMatter is anything that occupies space and has mass.Mass is the quantity of matter an object has.
4 Elements and Atoms Chapter 2 Section 1 Composition of MatterChapter 2Elements and AtomsElements are made of a single kind of atom and cannot be broken down by chemical means into simpler substances.Atoms are composed of protons, neutrons, and electrons.
5 Elements and Atoms, continued Section 1 Composition of MatterChapter 2Elements and Atoms, continuedThe NucleusProtons and neutrons make up the nucleus of the atom.Protons are positively charged particles.Neutrons have no charge (neutral).Together the mass of the protons and neutrons in the nucleus of an atom makes up the atom’s atomic mass.
6 Elements and Atoms, continued Section 1 Composition of MatterChapter 2Elements and Atoms, continuedElectronsElectrons move about the nucleus in orbitals.An orbital is a three- dimensional region around a nucleus that indicates the probable location of an electron.
7 Elements and Atoms, continued Section 1 Composition of MatterChapter 2Elements and Atoms, continuedIsotopesAtoms of the same element that have a different number of neutrons are called isotopes.
8 Section 1 Composition of Matter Chapter 2CompoundsCompounds consist of atoms of two or more elements that are joined by chemical bonds in a fixed proportion.
9 Chapter 2 Compounds, continued Covalent Bonds Section 1 Composition of MatterChapter 2Compounds, continuedCovalent BondsA covalent bond is formed when two atoms share electrons.
10 Chapter 2 Compounds, continued Ionic Bonds Section 1 Composition of MatterChapter 2Compounds, continuedIonic BondsAn ionic bond is formed when one atom gives up an electron to another. The positive ion is then attracted to a negative ion to form the ionic bond.
11 Section 1 Composition of Matter Chapter 2Ionic Bonding
12 Section 2 EnergyChapter 2ObjectivesDescribe the physical properties of each state of matter.Describe the role of reactants and products in chemical reactions.Explain the relationship between enzymes and activation energy.Explain how oxidation and reduction reactions are linked.
13 Chapter 2 Energy and Matter States of Matter Section 2 EnergyChapter 2Energy and MatterStates of MatterAddition of energy to a substance can cause its state to change from a solid to a liquid and from a liquid to a gas.
14 Energy and Chemical Reactions Section 2 EnergyChapter 2Energy and Chemical ReactionsReactants are substances that enter chemical reactions.Products are substances produced by chemical reactions.
15 Energy and Chemical Reactions Section 2 EnergyChapter 2Energy and Chemical Reactions
16 Energy and Chemical Reactions, continued Section 2 EnergyChapter 2Energy and Chemical Reactions, continuedActivation EnergyEnzymes lower the amount of activation energy necessary for a reaction to begin in living systems.Oxidation Reduction ReactionsA chemical reaction in which electrons are exchanged between atoms is called an oxidation-reduction reaction.
17 Chapter 2 Objectives Describe the structure of a water molecule. Section 3 Water and SolutionsChapter 2ObjectivesDescribe the structure of a water molecule.Explain how water’s polar nature affects its ability to dissolve substances.Outline the relationship between hydrogen bonding and the different properties of water.Identify the roles of solutes and solvents in solutions.Differentiate between acids and bases.
18 Section 3 Water and Solutions Chapter 2PolarityWater is considered to be a polar molecule due to an uneven distribution of charge.The electrons in a water molecule are shared unevenly between hydrogen and oxygen.
19 Chapter 2 Polarity, continued Solubility of Water Section 3 Water and SolutionsChapter 2Polarity, continuedSolubility of WaterThe polarity of water makes it effective at dissolving other polar substances such as sugars, ionic compounds, and some proteins.
20 Chapter 2 Hydrogen Bonding Section 3 Water and SolutionsChapter 2Hydrogen BondingA hydrogen bond is the force of attraction between a hydrogen molecule with a partial positive charge and another atom or molecule with a partial or full negative charge.
21 Hydrogen Bonding, continued Section 3 Water and SolutionsChapter 2Hydrogen Bonding, continuedCohesion and AdhesionCohesion is an attractive force that holds molecules of a single substance together, such as water molecules.Adhesion is the attractive force between two particles of different substances, such as water molecules and glass molecules.
22 Hydrogen Bonding, continued Section 3 Water and SolutionsChapter 2Hydrogen Bonding, continuedTemperature ModerationWater has the ability to absorb a relatively large amount of energy as heat and the ability to cool surfaces through evaporation.Density of IceSolid water is less dense than liquid water due to the shape of the water molecule and hydrogen bonding.
23 Section 3 Water and Solutions Chapter 2SolutionsA solution consists of a solute dissolved in a solvent.
24 Acids and Bases, continued Section 3 Water and SolutionsChapter 2Acids and Bases, continuedIonization of WaterWater ionizes into hydronium ions (H3O+) and hydroxide ions (OH–).AcidsAcidic solutions contain more hydronium ions than hydroxide ions.
25 Acids and Bases, continued Section 3 Water and SolutionsChapter 2Acids and Bases, continuedBasesBasic solutions contain more hydroxide ions than hydronium ions.BuffersBuffers are chemicals that neutralize the effects of adding small amounts of either an acid or a base to a solution.
26 Acids and Bases, continued Section 3 Water and SolutionsChapter 2Acids and Bases, continuedpHScientists have developed a scale for comparing the relative concentrations of hydronium ions and hydroxide ions in a solution. This scale is called the pH scale, and it ranges from 0 to 14.
27 Section 3 Water and Solutions Chapter 2The pH Scale