Chapter 11 Matter and Change 11.1 Describing Chemical Reactions 11.2 Types of Chemical Reactions 11.3 Reactions in Aqueous Solution

Introduction to Chemical Equations Write down word equations for 3 chemical reactions that you have seen or heard of.

Introduction to Chemical Equations Chemical Reaction Atoms of one or more substances are rearranged to form different chemical compounds.

Signs of a Chemical Reaction Transfer of energy Change in color Introduction to Chemical Equations Signs of a Chemical Reaction Transfer of energy Change in color Production of a gas Formation of a precipitate

Iron + oxygen → iron(III) oxide Introduction to Chemical Equations Word Equations Reactants → Products Iron + oxygen → iron(III) oxide Iron reacts with oxygen to produce iron(III) oxide (rust)

Equations that show just formulas of the reactants and products. Introduction to Chemical Equations Skeleton Equations Equations that show just formulas of the reactants and products. Fe + O2 → Fe2O3

Coefficients are used to balance reactants and products. Introduction to Chemical Equations Balanced Equation Coefficients are used to balance reactants and products. 4Fe + 3O2 → 2Fe2O3

Balancing Chemical Equations Coefficients— small whole numbers put in front of formulas in an equation to balance it. Add coefficients to balance the reactants and products. Do not add subscripts!

Law of Conservation of Mass Balancing Chemical Equations Law of Conservation of Mass During a chemical reaction, the mass of the products always equals the mass of the reactants. Atoms are neither created nor destroyed in ordinary chemical reactions. The same number of atoms of each element must be present on both sides of the equation.

Balancing a Chemical Equation Sample Problem 11.2 Balancing a Chemical Equation AgNO3 + Cu → Cu(NO3)2 + Ag

Balancing a Chemical Equation Sample Problem 11.2 Balancing a Chemical Equation 2AgNO3 + Cu → Cu(NO3)2 + 2Ag

Balancing a Chemical Equation Sample Problem 11.3 Balancing a Chemical Equation Aluminum is a good choice for outdoor furniture because it reacts with oxygen in the air to form a thin protective coat of aluminum oxide. Balance this equation. Al + O2 → Al2O3

Balancing a Chemical Equation Sample Problem 11.3 Balancing a Chemical Equation Aluminum is a good choice for outdoor furniture because it reacts with oxygen in the air to form a thin protective coat of aluminum oxide. Balance this equation. 4Al + 3O2 → 2Al2O3

C3H8(g) + O2(g) → CO2(g) + H2O(l) Balance the following equation. C3H8(g) + O2(g) → CO2(g) + H2O(l)

C3H8(g) + O2(g) → CO2(g) + H2O(l) Balance the following equation. C3H8(g) + O2(g) → CO2(g) + H2O(l) C3H8(g) + 5O2(g) → 3CO2(g) + 4H2O(l)

http://ed.ted.com/lessons/the-law-of-conservation-of-mass-todd-ramsey http://phet.colorado.edu/blog/2014/09/08/new-html5-balancing-chemical-equations-simulation/

Molecules and Molecular Compounds Remember HOFBrINCl molecules! These elements are always found in nature in the form of diatomic molecules. Write them as such in your skeleton equations! HOFBrINCl Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved.

Symbols Used in Chemical Equations Interpret Data Symbols Used in Chemical Equations Symbol Explanation + Separates two reactants or two products → “Yields,” separates reactants from products Use in place of → for reversible reactions (s), (l), (g) Designates a reactant or product in the solid state, liquid state, or gaseous state; placed after the formula (aq) Designates an aqueous solution; the substance is dissolved in water; placed after the formula Indicates that heat is supplied to the reaction A formula written above or below the yields sign indicates its use as a catalyst (in this example, platinum). Δ heat Pt

END OF 11.1