Chemical Reactions Physical Science Chemical Reactions When 2

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Chemical Reactions Physical Science

Chemical Reactions Physical Science

Chemical Reactions • When 2 or more elements chemically combine to form a “new”

Chemical Reactions • When 2 or more elements chemically combine to form a “new” substance

Chemical Equation • Is a representation of a chemical reaction • Two Parts •

Chemical Equation • Is a representation of a chemical reaction • Two Parts • Reactants • Products

Reactants vs Products C + O 2 CO 2 The arrow ( ) divides

Reactants vs Products C + O 2 CO 2 The arrow ( ) divides an equation in half • Reactants – The substance(s) that undergo the change – All things on the left side of the “ ” – Ex: C & O 2 • Products – The new substance(s) that form – All things on the right side of the “ ” – Ex: CO 2

Id the Reactants and Products 1) 2 Cu + O 2 2 Cu. O

Id the Reactants and Products 1) 2 Cu + O 2 2 Cu. O 2) 2 KCl. O 3 2 KCl + 3 O 2 3) HCl + Na. OH Na. Cl + H 2 O 4) N 2 H 4 + O 2 N 2 + 2 H 2 O

Endothermic vs Exothermic • Endothermic – Reaction absorbs energy from its surrounding – Surrounding

Endothermic vs Exothermic • Endothermic – Reaction absorbs energy from its surrounding – Surrounding becomes cooler • Exothermic – Reaction releases energy to the surrounding – Surrounding becomes warmer

Signs of a Reaction • Production of a GAS – Fizzing, bubbling • Formation

Signs of a Reaction • Production of a GAS – Fizzing, bubbling • Formation of a Precipitate – Insoluble solid • Energy is released – EX: Light, heat • Color Change

Counting Atoms • Number in front is called a coefficient • Coefficients are multiplied

Counting Atoms • Number in front is called a coefficient • Coefficients are multiplied to all elements behind it • Subscripts go to what they follow

Counting Atoms Practice 1) 2 CO 2 2) Mg(OH)2 3) 3 Ca(NO 3)2 4)

Counting Atoms Practice 1) 2 CO 2 2) Mg(OH)2 3) 3 Ca(NO 3)2 4) NH 4 OH

End of Day One

End of Day One

How Do I Balance an Equation? • ID the elements present • Count the

How Do I Balance an Equation? • ID the elements present • Count the amount of atoms on both sides of the “ ” for each element • Place coefficients in front of compounds and multiply to any subscript • Recount the atoms on both sides of the “ ” to see if they are equal. If not equal, adjust the coefficients LEFT has to equal RIGHT

Balancing Practice #1 ____Cu + ____O 2 ____Cu. O

Balancing Practice #1 ____Cu + ____O 2 ____Cu. O

Balancing Practice #2 ____N 2 H 4 + ____O 2 ____N 2 + ____H

Balancing Practice #2 ____N 2 H 4 + ____O 2 ____N 2 + ____H 2 O

Balancing Practice #3 ____KCl. O 3 ____KCl + ____O 2

Balancing Practice #3 ____KCl. O 3 ____KCl + ____O 2

Choose the Balanced Equation • KCl. O 2 KCl + 2 O 2 •

Choose the Balanced Equation • KCl. O 2 KCl + 2 O 2 • 4 Al + 3 O 2 2 Al 2 O 3 • N 2 + 3 H 2 2 NH 3 • H 2 + O 2 H 2 O • 2 Na. Cl 2 Na + Cl 2

Why Balance? • The Law of Conservation of Matter – Matter is neither created

Why Balance? • The Law of Conservation of Matter – Matter is neither created nor destroyed – Start = Finish

End of Day Two

End of Day Two

Types of Reactions • 4 Main Types – Synthesis – Decomposition – Single Replacement

Types of Reactions • 4 Main Types – Synthesis – Decomposition – Single Replacement – Double Replacement • 2 Special Types – Combustion Reaction – Neutralization Reaction

Synthesis Reaction A + B AB • When 2 or more substances react to

Synthesis Reaction A + B AB • When 2 or more substances react to form a single substance • 2 1 • Dating: Becoming a Couple

Decomposition Reaction AB A + B • When a compound breaks down into two

Decomposition Reaction AB A + B • When a compound breaks down into two or more substances • 1 2 • Dating: Breaking Up

Single Replacement Reaction A + BC B + AC • A reaction in which

Single Replacement Reaction A + BC B + AC • A reaction in which one element trades places with another element in a compound • Element and Compound • Dating: CHEATING

Double Replacement Reaction AB + CD AD + BD • Where two different compounds

Double Replacement Reaction AB + CD AD + BD • Where two different compounds exchange positive ions (cations) to form two new compounds • All compounds – (4 of them) • Dating: Swingers

Type Of Reaction Practice 1. Na 3 PO 4 + 3 KOH 3 Na.

Type Of Reaction Practice 1. Na 3 PO 4 + 3 KOH 3 Na. OH + K 3 PO 4 2. P 4 + 3 O 2 2 P 2 O 3 3. Pb + Fe. SO 4 Pb. SO 4 + Fe 4. Ca. CO 3 Ca. O + CO 2

Special Reaction: Combustion Reaction • When a hydrocarbon (hydrogen and carbon together) reacts with

Special Reaction: Combustion Reaction • When a hydrocarbon (hydrogen and carbon together) reacts with Oxygen • Products are always CO 2 & H 2 O • Ex: CH 4 + 2 O 2 CO 2 + H 2 O

End of Unit!

End of Unit!