Unit 5: Chemical Bonds and Reactions 2015
Stevens / 1

Unit 5: Chemical Bonds & Reactions Notes Packet

VOCABULARY:

Term / Definition / Example
Chemical Bonds
Valence Electron / Electron in the outermost shell of an atom that determines the atoms chemical properties
Ionic Bond
Covalent Bond
Metallic Bond / A bond formed by the attraction between positively charged metal ions and the electrons around them
Molecule
Compound / Substance made up of atoms of two or more different elements joined by chemical bonds
Chemical Reaction
Chemical Equation / Representation of a chemical reaction that uses symbols to show the relationship between reactants and products
Reactant
Product
Coefficient
Subscript / Small number in a chemical equation that comes after a certain element and tells you how many atoms of that element you have
Catalyst
Inhibitor
Endothermic Rxn
Exothermic Rxn / Rxn in which energy is released to the surrounding environment as heat
Decomposition Rxn
Synthesis Rxn
Combustion Rxn / Oxidation rxn of an organic compound where heat is released
Single Replacement Rxn
Double Replacement Rxn / Rxn in which a gas, solid, or compound forms from the exchange of atoms or ions between two compounds
Nuclear Reaction
Photosynthesis
Cellular Respiration

Section 1:

Key Ideas:

•What kinds of bonds form in chemical reactions?

Vocabulary:

•Chemical bonds- Molecule

•Valence electrons- Compound

•Ionic bonds- Metallic Bond

•Covalent bond

How do atoms (like H2O) stay together?

  • Chemical Bonds
  • A force of ______that holds two atoms together
  • Has a significant effect on chemical and physical properties of compounds
  • Involves the ______
  • Valence Electrons: the electrons in the outermost energy level of an atom that ______

Counting Valence Electrons (Draw and Label each picture)

Determining the Number of Valence Electrons by Using the Periodic Table

*Atoms of elements in Groups 1 and 2 have the same number of valence electrons as their group number (so 1 or 2)

*Atoms of elements in Group 3-12 do not have a general rule relating their valence electrons to their group number. However, they typically have between 1 or 2 valence electrons.

*Atoms of elements in Groups 13-18 have 10 fewer valence electrons than their group number. (Exception - helium atoms have only 2 valence electrons, even though they are in group 18)

How Many Valence Electrons? How do you know?

Hydrogen

Lead

Xenon

Sulfur

Rubidium

The Octet Rule

______

______

Atoms with less than 4 electrons tend to ______electrons.

Atoms with more than 4 electrons tend to ______electrons.

Atoms with exactly 4 electrons tend to ______electrons.

There are always exceptions!

•What happens with an atom like Hydrogen, who only has 1 electron, and only needs 2 to fill its outer shell? ______

The Octet Rule In Action – Draw and describe how Sodium and Chlorine combine.

Lewis Structure - (Electron Dot Diagram)

  • A way of drawing the outer energy level electrons (valence) of an atom
  • The symbol for the element surrounded by as many dots as there are electrons in its outer energy level (valence)

Examples: Draw Al, N and Mg. How many valence electrons does each have?

3 Types of Chemical Bonds

What can you describe about each of these types of bonds just by looking at the name?

  • Ionic:______
  • Covalent: ______
  • Metallic: ______

IONIC BONDS

  • ______
  • ______
  • Forms between atoms of ______and atoms of ______
  • Resulting compounds have a name that usually ends in ______
  • ______not ______!
  • Example: ______

COVALENT BOND

  • ______
  • Each pair of shared electrons creates a bond
  • ______
  • Example: ______

Types of Covalent Bonds

Different covalent bond types share a different number of electrons – Draw and label the examples

METALLIC BOND

  • A force of attraction between a positively charged metal ion and the electrons in a metal
  • ______
  • Many properties of metals, such as conductivity and malleability, result from the freely moving electrons in the metal

RESULTS OF BONDING

SECTION 2:

•Key Ideas:

• When do chemical reactions take place?

• What is the role of energy in chemical reactions?

• What is a chemical equation?

• How do I understand what a chemical equation is telling me?

• What is photosynthesis? What are the reactants and products?

• What is cellular respiration? What are the reactants and products?

•Vocabulary:

•Chemical Reactions- Endothermic Rxn

•Chemical Equation- Exothermic Rxn

•Reactant

•Product

•Coefficient

•Subscript

CHEMICAL REACTIONS (RXN):

•Chemical Change occurs

•______

•One or more substances change to produce one or more different substances

•______

•Many forms of energy can be used:

•______

•______

•______

•______

•______

Remember!!! ______

Reminder:

CHEMICAL CHANGE:

•a change in which a substance becomes another substance having different properties

•a change that is not reversible using ordinary physical means

•Changes that usually cause, heat, sound, light, odor, fizzing/foaming, color changes

CHEMICAL EQUATION:

•Shorthand form for writing what compounds are used to begin the reaction and what compounds are formed after the reaction occurs

•Examples:

2H2 + O2 2H2O

CH4+2O2 CO2+2H2O

C6H12O6 + 6O2  6CO2 + 6H2O + energy

PARTS OF A CHEMICAL EQUATION: Label them all!

______

2H2 + O2 2H2O

•What does a Coefficient mean? ______

______

•What does a subscript mean? ______

______

•What does “Yield” mean? ______

•Reactants are always on what side of the yield sign? ______

•Products are always on what side of the yield sign? ______

SYMBOLS OF A CHEMICAL EQUATION:

Example:

PRACTICE:

•In CO2 (carbon dioxide) how many Carbon atoms are there? How many Oxygen atoms? ______

•In 2NH3, (windex) how many Nitrogen atoms are there? How many Hydrogen atoms? ______

•In H2SO4 (battery acid) how many of each type of atom is there? ______

•In 3CHNaO3 (Alka Seltzer), how many of each type of atom is there? ______

•In C9H8O4 (aspirin), how many of each type of atom is there? ______

•What kind of bonds do you think these all form? Why?

Compound / Type of Bond / Why?
CO2
2NH3
H2SO4
3CHNaO3
C9H8O4

WHAT IS PHOTOSYNTHESIS?

•Photosynthesis is: basically how plants make their own food!

•How does it work? Draw and label diagram.

Photosynthesis formula:

1. What are the reactants in photosynthesis? ______

2. What are the products? ______

3. What is the catalyst? ______

WHAT IS CELLULAR RESPIRATION?

•How cells in organisms use oxygen and sugar to make energy needed for us to survive

•How does it work? Draw and label diagram.

Cellular Respiration formula:

1. What are the reactants in cellular respiration? ______

2. What are the products? ______

HOW ARE PHOTOSYNTHESIS AND CELLULAR RESPIRATION RELATED? ______

ENERGY AND CHEMICAL REACTIONS:

RATES OF CHEMICAL REACTIONS:

The rates at which chemical reactions can take place areinfluenced by the following:

•Temperature –a measure of the average kinetic energy of the particles in a sample of matter

•Ex. Increasing the temperature when cooking increases reaction rate

•Surface area – amount of material that comes into contact with the reactants

•Ex. Cutting a potato into smaller pieces when cooking (larger surface area (smaller pieces) increases reaction rate)

•Concentration – amount of substance per volume

•Ex. Turning the valve on a gas stove to increase the concentration of methane molecules (this will increase the rate of rxn)

•Ex. Too much salt in a glass of water will decrease the rate of rxn

•Catalysts (enzymes) –______

______

•Inhibitors – ______

______

SECTION 3:

Key Ideas:

• What are different types of chemical reactions?

• How is a nuclear reaction different than a chemical reaction?

Vocabulary:

•Synthesis Reaction - Nuclear Reaction

•Decomposition Reaction- Fission/Fusion

•Combustion

•Single Replacement Rxn

•Double Replacement Rxn

TYPES OF CHEMICAL REACTION

•4Types

•Synthesis (creating)

•Decomposition (separating)

•Combustion (burning)

•Displacement/Replacement (switching)

SYNTHESIS (CREATING)

•______

•Ex: Synthesis of Carbon Dioxide
2CO(g) + O2(g) → 2CO2(g)

DECOMPOSITION (SEPARATING)

•______

•Ex: Electrolysis of water to make hydrogen and oxygen

•2 H2O ---> 2 H2+ O2

COMBUSTION (BURNING)

•______

•Oxygen reacts with another element or compound to form water (H2O), carbon dioxide (CO2) and heat

•______

DISPLACEMENT/REPLACEMENT (SWITCHING)

•Two types: Single replacement and double replacement

•Single replacement (substitution): ______

•Ex: Zn + 2 HCl → ZnCl2+ H2

•Ex:

•Double Replacement: ______

______

•Ex: AgNO3+ HCl→ AgCl + HNO3

•Ex: Fe2O3+ HCl → FeCl3+ H2O

CHEMICAL VS NUCLEAR RXN: