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Chapter Presentation

Transparencies Standardized Test Prep

Visual Concepts

Resources



Section 1 Composition of MatterChapter 2

Objectives

• Define 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.



Chemistry of LifeChapter 2

Table of Contents

Section 1 Composition of Matter

Section 2 Energy

Section 3 Water and Solutions



At the Bell Review1) Major characteristics all living things have in common are

a.metabolism b. response to stimuli

c.both a and b d. neither a nor b

2) 750 grams = _____ kg.

a.7,500 b. 7.50

c.0.750 d. 0.0750

3) The ocular lens in a microscope has a 10x magnification and the objective lens has a 40x magnification. The total magnification is

a.4x b. 40x

c. 400x d. 4,000x

4) Describe how natural selection causes adaptations in organisms.

5) Pairs of electrons are shared between atoms in a covalent bond.

TRUE or FALSE



Big Ideas

• Life emerges due to the chemical organization of matter into cells.

• Structure is related to function at all biological levels of organization.

• Eukaryotic cells can differentiate and organize

making it possible for multicellularity.




Matter

• Matter is anything that occupies space and has mass.

• Mass is the quantity of matter an object has.




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.

• http://ptable.com/




Elements and Atoms, continued

• The Nucleus– Protons and neutrons make up the nucleus of the

atom.





• 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.





• Isotopes

– Atoms of the same element that have a different number of neutrons are called isotopes.




Compounds

• Compounds consist of atoms of two or more elements that are joined by chemical bonds in a fixed proportion.



Chapter 2

Keystone Bio Question


Carbon is found in all known forms of life. Which statement best describes why carbon is

uniquely suited to forming macromolecules such as those found in living organisms?

A. Carbon forms large, flat compounds that have increased surface area available for reactions.

B. Carbon forms large, three-dimensional compounds that are not chemically reactive.

C. Carbon forms strong, stable bonds with up to four other atoms, including carbon atoms.

D. Carbon forms weak bonds with other atoms that can be easily broken to release energy.




Compounds, continued

• Covalent Bonds– A covalent bond is

formed when two atoms share electrons.




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.



Chapter 2

Ionic Bonding




Section 2 EnergyChapter 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.




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.




Energy and Chemical Reactions

• Reactants are substances that enter chemical reactions.

• Products are substances produced by chemical reactions.



Chapter 2

Energy and Chemical Reactions

Section 2 Energy




Energy and Chemical Reactions, continued

• Activation Energy– Enzymes lower the amount of activation energy

necessary for a reaction to begin in living systems.

– Enzymes are

Biological catalysts.(reduce amount

of energy needed

for reaction to take place)



https://

www.youtube.com/watch?

v=YacsIU97OFc




Energy and Chemical Reactions, continued

• Oxidation Reduction Reactions– A chemical reaction in which electrons are

exchanged between atoms is called an oxidation-reduction reaction.

– Oxidation: a reactant loses one or more electrons (becomes more positive)

– Reduction: a reactant gains one or more electrons (becomes more negative)



Section 3 Water and SolutionsChapter 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.




Polarity

• Water = polar molecule • due to an uneven distribution of charge

• Electrons in a water molecule are shared unevenly between hydrogen and oxygen.




Polarity, continued

• Solubility of Water– polarity of water makes it effective at dissolving

other polar substances – Ex. sugars, ionic compounds, and some

proteins




Hydrogen Bonding

• hydrogen bond = 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

• Cohesion and Adhesion– Cohesion = attractive force that holds molecules

of a single substance together– Ex. Group of water molecules

– Adhesion = attractive force between two particles of different substances

– Ex. water molecules & glass molecules




Solutions

• solution = solute + solvent• Ex. Solute = Kool-aid

• Ex. Solvent = water




Solutions

• Aqueous solution water is the solvent

• Concentration varies with amount of solute

• Example: add 2 g of kool aid powder to 100 mL of water

What is the concentration?

2%

• Raise the concentration by adding more powder (solute) to the water (solvent).




Acids and Bases

• Ionization of Water

– Water ionizes into hydronium ions (H3O+) and hydroxide ions (OH–).




Acids and Bases, continued

• Acids– Acidic solutions = more hydronium ions

– Example: Dissolved HCl in water adds H+

And creates H3O (hydronium ion)

• Bases– Basic solutions = more hydroxide ions

– Example: Dissolved NaOH in water adds OH- (hydroxide ions)

(pg 43)





• pH– pH scale – compares concentrations of hydronium

ions to hydroxide ions in a solution– ranges from 0 (acidic) to 14 (basic)

– 7 = neutral



Chapter 2

The pH Scale

Section 3 Water and Solutions





• pH

– The change of one pH unit reflects a ten fold change in acidity or alkalinity

– Ex. Something with a pH of 6 has 10x more hydronium ions than something with a pH of 7

– Ex. Vinegar has 1,000 x more hydronium ions (pH of 3) than rainwater (pH of 6).

– Move 3 on pH scale 103

– 10x10x10

– Move 4 on pH scale 104

– 10x10x10x10

– http://www.sciencebuddies.org/science-fair-projects/project_ideas/Chem_AcidsBasespHScale.shtml





• Buffers– Buffers = neutralize

– either by adding acid or base

– Ex: taking tums after eating acidic foods– Base neutralizes acid (acts as a buffer)



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

Standardized Test PrepChapter 2



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





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





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

Chapter 2

The graph below shows the energy in a chemical reaction as the reaction progresses. Use the graph to answer the questions that follow.

Standardized Test Prep




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

Chapter 2






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

Chapter 2






6. Oxidation : loss :: reduction :

F. win

G. gain

H. take

J. forfeit

Chapter 2 Standardized Test Prep



Multiple Choice, continued7. 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.

Chapter 2

The illustration below is a space-filling model of water. Use the model to answer the following question.




Short Response

Covalent bonding is a sharing of electrons between atoms. Why do some atoms share electrons?




Short Response, continued

Covalent bonding is a sharing of electrons between atoms. Why do some atoms share electrons?

Answer:

Sharing electrons achieves a stable number of electrons in the orbitals that correspond to the highest energy level for each atom.




Extended Response

Pure water contains equal numbers of hydronium ions and hydroxide ions and is therefore a neutral solution.

Part A What is the initial cause of the dissociation of water molecules into hydrogen and hydroxide

ions? Explain the process.

Part B After water dissociates, hydronium ions are formed. Explain this process.




Extended Response, continued

Answer:Part A Water molecules collide as they move about.

Some collisions result in the loss of a hydrogen nucleus. Thus, the water molecule gives rise to a hydrogen ion and a hydroxide ion.

Part B The hydrogen ion from the initial dissociation of water combines with another water molecule to form a hydronium ion.





Elements and Atoms




Compounds




Energy and Matter




Hydrogen Bonding

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