Chapter 2 Chemistry of Life Revised by R. LeBlanc

Chapter 2 Matter Matter is anything that occupies space and has mass. Section 1 Composition of Matter Chapter 2 Matter Matter is anything that occupies space and has mass. Mass is the quantity of matter an object has.

Section 1 Composition of Matter Chapter 2 Matter

Chapter 2 Elements and Atoms Section 1 Composition of Matter Chapter 2 Elements and Atoms Elements 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. Where are elements listed? In what order are the elements listed?

Section 1 Composition of Matter Chapter 2 Element

Elements and Atoms, continued Section 1 Composition of Matter Chapter 2 Elements and Atoms, continued The Nucleus Protons and neutrons make up the nucleus of the atom.

Elements and Atoms, continued Section 1 Composition of Matter Chapter 2 Elements and Atoms, continued Electrons Electrons move about the nucleus in orbitals. An orbital is a three-dimensional region around a nucleus that indicates the probable location of an electron.

Elements and Atoms, continued Section 1 Composition of Matter Chapter 2 Elements and Atoms, continued Isotopes Atoms of the same element that have a different number of neutrons are called isotopes.

Section 1 Composition of Matter Chapter 2 Compounds Compounds consist of atoms of two or more elements that are joined by chemical bonds in a fixed proportion.

Section 1 Composition of Matter Chapter 2 Compounds

Chapter 2 Compounds, continued Ionic Bonds Section 1 Composition of Matter Chapter 2 Compounds, continued Ionic Bonds An 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.

Section 1 Composition of Matter Chapter 2 Ionic Bonding

Section 1 Composition of Matter Chapter 2 Ionic Bonding

Chapter 2 Compounds, continued Covalent Bonds Section 1 Composition of Matter Chapter 2 Compounds, continued Covalent Bonds A covalent bond is formed when two atoms share electrons.

Section 1 Composition of Matter Chapter 2 Covalent Bonding

Section 2 Energy Chapter 2 Objectives Describe 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.

Chapter 2 Energy and Matter States of Matter Section 2 Energy Chapter 2 Energy and Matter States of Matter Addition of energy to a substance can cause its state to change from a solid to a liquid and from a liquid to a gas.

Section 2 Energy Chapter 2 Energy

Energy and Chemical Reactions Section 2 Energy Chapter 2 Energy and Chemical Reactions Reactants are substances that enter chemical reactions. Products are substances produced by chemical reactions. Chemical Equation for Photosynthesis: 6CO2 + 6H2O  C6H1206 + 6O2

Energy and Chemical Reactions Section 2 Energy Chapter 2 Energy and Chemical Reactions

Energy and Chemical Reactions, continued Section 2 Energy Chapter 2 Energy and Chemical Reactions, continued Activation Energy Enzymes lower the amount of activation energy necessary for a reaction to begin in living systems.

Activation Energy and Chemical Reactions Section 2 Energy Chapter 2 Activation Energy and Chemical Reactions

Photosynthesis Process of using carbon dioxide, water and energy to create glucose (food) for use by a plant 6CO2 + 6H2O + Energy = C6H12O6 +6O2 What are the reactants in this reaction? What are the products?

Energy and Chemical Reactions, continued Section 2 Energy Chapter 2 Energy and Chemical Reactions, continued Oxidation Reduction Reactions A chemical reaction in which electrons are exchanged between atoms is called an oxidation-reduction reaction.

Chapter 2 Objectives Describe the structure of a water molecule. Section 3 Water and Solutions Chapter 2 Objectives Describe 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.

Section 3 Water and Solutions Chapter 2 Polarity Water 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.

Chapter 2 Polarity, continued Solubility of Water Section 3 Water and Solutions Chapter 2 Polarity, continued Solubility of Water The polarity of water makes it effective at dissolving other polar substances such as sugars, ionic compounds, and some proteins.

Section 3 Water and Solutions Chapter 2 Solutions A solution consists of a solute dissolved in a solvent.

Salt dissolving in water Hydrogen bonds make water a good solvent. Water molecules form shells around positive and negative ions, eliminating their attraction for each other.

Salt dissolving in water

Chapter 2 Hydrogen Bonding Section 3 Water and Solutions Chapter 2 Hydrogen Bonding A 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.

Hydrogen Bonding, continued Section 3 Water and Solutions Chapter 2 Hydrogen Bonding, continued Cohesion and Adhesion Cohesion 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.

Comparing Cohesion and Adhesion Section 3 Water and Solutions Chapter 2 Comparing Cohesion and Adhesion

How does water get to the leaves of trees hundreds of feet tall? Click to view animation. animation

Cohesion and Adhesion in Transpiration Woody walls in a plant called xylem. Cohesion and adhesion cause capillary action. Water meniscuses become more concave, increasing the surface tension. Water moves from the roots up to the leaves of a tree.

Hydrogen Bonding, continued Section 3 Water and Solutions Chapter 2 Hydrogen Bonding, continued Temperature Moderation Water has the ability to absorb a relatively large amount of energy as heat and the ability to cool surfaces through evaporation.

Hydrogen Bonding, continued Section 3 Water and Solutions Chapter 2 Hydrogen Bonding, continued Density of Ice Solid water is less dense than liquid water due to the shape of the water molecule and hydrogen bonding.

Chapter 2 Acids and Bases Ionization of Water Section 3 Water and Solutions Chapter 2 Acids and Bases Ionization of Water Water ionizes into hydronium ions (H3O+) and hydroxide ions (OH–).

Acids and Bases, continued Section 3 Water and Solutions Chapter 2 Acids and Bases, continued Acids Acidic solutions contain more hydronium ions than hydroxide ions.

Acids and Bases, continued Section 3 Water and Solutions Chapter 2 Acids and Bases, continued Bases Basic solutions contain more hydroxide ions than hydronium ions.

Section 3 Water and Solutions Chapter 2 Bases

Acids and Bases, continued Section 3 Water and Solutions Chapter 2 Acids and Bases, continued pH Scientists 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.

Section 3 Water and Solutions Chapter 2 The pH Scale

Acids and Bases, continued Section 3 Water and Solutions Chapter 2 Acids and Bases, continued Buffers Buffers are chemicals that neutralize the effects of adding small amounts of either an acid or a base to a solution.

Section 3 Water and Solutions Chapter 2 pH

Chapter 2 Multiple Choice Standardized Test Prep Multiple Choice 1. The way in which elements bond to form compounds depends on which of the following? A. the model of the atom B. the structural formula of the compound C. the dissociation of the ions in the compound D. the number and arrangement of electrons in the atoms of the elements

Multiple Choice, continued Chapter 2 Standardized Test Prep Multiple Choice, continued 1. The way in which elements bond to form compounds depends on which of the following? A. the model of the atom B. the structural formula of the compound C. the dissociation of the ions in the compound D. the number and arrangement of electrons in the atoms of the elements

Multiple Choice, continued Chapter 2 Standardized Test Prep Multiple Choice, continued 2. If an atom is made up of 6 protons, 7 neutrons, and 6 electrons, what is its atomic number? F. 6 G. 7 H. 13 J. 19

Multiple Choice, continued Chapter 2 Standardized Test Prep Multiple Choice, continued 2. If an atom is made up of 6 protons, 7 neutrons, and 6 electrons, what is its atomic number? F. 6 G. 7 H. 13 J. 19

Multiple Choice, continued Chapter 2 Standardized Test Prep Multiple Choice, continued The graph below shows the energy in a chemical reaction as the reaction progresses. Use the graph to answer the questions that follow. 3. The amount of energy needed for this chemical reaction to begin is shown by the line rising from the reactants. What is this energy called? A. chemical energy B. electrical energy C. activation energy D. mechanical energy

Multiple Choice, continued Chapter 2 Standardized Test Prep Multiple Choice, continued The graph below shows the energy in a chemical reaction as the reaction progresses. Use the graph to answer the questions that follow. 3. The amount of energy needed for this chemical reaction to begin is shown by the line rising from the reactants. What is this energy called? A. chemical energy B. electrical energy C. activation energy D. mechanical energy

Multiple Choice, continued Chapter 2 Standardized Test Prep Multiple Choice, continued The graph below shows the energy in a chemical reaction as the reaction progresses. Use the graph to answer the questions that follow. 4. Suppose that this reaction needs a catalyst to proceed. In the absence of a catalyst, the activation energy would be which of the following? F. larger than what is shown G. the same as what is shown H. smaller than what is shown J. not much different from what is shown

Multiple Choice, continued Chapter 2 Standardized Test Prep Multiple Choice, continued The graph below shows the energy in a chemical reaction as the reaction progresses. Use the graph to answer the questions that follow. 4. Suppose that this reaction needs a catalyst to proceed. In the absence of a catalyst, the activation energy would be which of the following? F. larger than what is shown G. the same as what is shown H. smaller than what is shown J. not much different from what is shown

Multiple Choice, continued Chapter 2 Standardized Test Prep Multiple Choice, continued The graph below shows the energy in a chemical reaction as the reaction progresses. Use the graph to answer the questions that follow. 5. What is an aqueous solution that contains more hydroxide ions than hydronium ions called? A. a gas B. a base C. a solid D. an acid

Multiple Choice, continued Chapter 2 Standardized Test Prep Multiple Choice, continued The graph below shows the energy in a chemical reaction as the reaction progresses. Use the graph to answer the questions that follow. 5. What is an aqueous solution that contains more hydroxide ions than hydronium ions called? A. a gas B. a base C. a solid D. an acid

Multiple Choice, continued Chapter 2 Standardized Test Prep Multiple Choice, continued 6. Oxidation : loss :: reduction : F. win G. gain H. take J. forfeit

Multiple Choice, continued Chapter 2 Standardized Test Prep Multiple Choice, continued 6. Oxidation : loss :: reduction : F. win G. gain H. take J. forfeit

Multiple Choice, continued Chapter 2 Standardized Test Prep Multiple Choice, continued The illustration below is a space-filling model of water. Use the model to answer the following question. 7. The covalent bonds on the water molecule depicted in the picture above has partial positive charges on the hydrogen atom and a partial negative charge on the oxygen atom. What do the partial positive and partial negative charges on this water molecule mean? A. Water is an ion. B. Water is a polar molecule. C. Water needs a proton and two electrons to be stable. D. Oxygen atoms and hydrogen atoms have opposite charges.

Multiple Choice, continued Chapter 2 Standardized Test Prep Multiple Choice, continued The illustration below is a space-filling model of water. Use the model to answer the following question. 7. The covalent bonds on the water molecule depicted in the picture above has partial positive charges on the hydrogen atom and a partial negative charge on the oxygen atom. What do the partial positive and partial negative charges on this water molecule mean? A. Water is an ion. B. Water is a polar molecule. C. Water needs a proton and two electrons to be stable. D. Oxygen atoms and hydrogen atoms have opposite charges.