Chemical Reactions

Warm Up

What is the mass of this object, with the appropriate number of significant figures.

What Makes a Reaction Chemical?

• Atoms are rearranged to form a new substance

• Evidence of a chemical reaction:– Heat

• Emitting• Absorbing

– Light– Color change– Odor– Gas bubbles– Formation of a solid

Terminology

• Reactant: starting substances• Product: substances produced during

the reaction• Symbols:

+ Separates two or more reactants or products

→ Represents the reaction, separates the reactants and products

Represents a reversible reaction, separates the reactants and products

(s) Solid state

(l) Liquid state

(g) Gaseous state

(aq) Water (aqueous) solution

Writing Chemical Reaction Equations

Reactant 1 + Reactant 2 → Product 1 + Product 2

Word Equations

Write a word equation that describes the reaction between Aluminum and Bromine1.Determine phase of each element: – Aluminum is a solid (s)– Bromine is a liquid (l)

2.Write word equation:Aluminum (s) + bromine (l) → aluminum bromide

(s)

3.Reads as: Aluminum and Bromine react to produce aluminum bromide

Skeleton Equations• Replace element names with chemical symbols• Indicate the number of atoms in the products1. Determine the chemical symbols for reactants

– Solid Aluminum = Al (s)– Liquid Bromine = Br2 (l)

2. Calculate chemical formula for products1. Figure out ionization state for each element

• Al +3

• Br-1

2. Criss Cross charges to find number of atoms of each element

1. Al1BR3

2. AlBr3

3. Replace words with chemical formulasAl (s) + Br2 (l) → AlBr3 (s)

Practice

Write a word equation and then skeleton equation for the following reactions:1. Hydrogen and Bromine gas react to

form hydrogen bromide2. Carbon monoxide and oxygen react

to form carbon dioxide

Types ofChemical Reactions

Aluminum & CuCl2 by Mr. W

/Synthesis/The get-together

/Synthesis/The get-together

Two or more chemicals bond togetherforming one new substance.

/Synthesis/The get-together

A + B AB

/Synthesis/The get-together

2Na + Cl2 2NaCl

/Decomposition/The break-up

One substance breaks down intotwo or more separate substances.

/Decomposition/The break-up

AB A + B

/Decomposition/The break-up

2H2O2 2H2O + O2

/Decomposition/The break-up

/Single Replacement/The cheater

One element knocks another elementout of a compound.

/Single Replacement/The cheater

AB + X AX + B

/Single Replacement/The cheater

2HCl + Zn ZnCl2 + H2

/Single Replacement/The cheater

/Double Replacement/The swap

Two compounds switch ionswith each other.

/Double Replacement/The swap

AB + XY AX + BY

/Double Replacement/The swap

BaCl2 + Na2SO4 BaSO4 + 2NaCl

/Double Replacement/The swap

/Combustion/Everyone loves O2

A compound burns in oxygen gas.

/Combustion/Everyone loves O2

A + O2

/Combustion/Everyone loves O2

Oxygen will always be a reactant.

2Mg + O2 2MgO

/Combustion/Everyone loves O2

Clicker Quiz Questions

• For each reaction, select the type of reaction from the types that we just learned.

• Options:A. DecompositionB. SynthesisC. Singe DisplacementD. Double DisplacementE. Combustion

Question 1

2H2 + O2 -> 2H2OA. DecompositionB. SynthesisC. Singe DisplacementD. Double DisplacementE. Combustion

Question 2

2KClO3 -> 2KCl + 3O2A. DecompositionB. SynthesisC. Singe DisplacementD. Double DisplacementE. Combustion

Question 3

Zn + 2HCl -> H2 + ZnCl2A. DecompositionB. SynthesisC. Singe DisplacementD. Double DisplacementE. Combustion

Question 4

2S + 3O2 -> 2SO3A. DecompositionB. SynthesisC. Singe DisplacementD. Double DisplacementE. Combustion

Question 5

H2SO4 + 2NaOH -> Na2SO4 + 2H2OA. DecompositionB. SynthesisC. Singe DisplacementD. Double DisplacementE. Combustion

Question 6

Ca(OH)2 -> CaO + H2OA. DecompositionB. SynthesisC. Singe DisplacementD. Double DisplacementE. Combustion

Question 7

H2 + 2AgNO3 -> 2Ag + 2HNO3A. DecompositionB. SynthesisC. Singe DisplacementD. Double DisplacementE. Combustion

Question 8

C10H8 + 12O2 -> 10CO2 + 4H2OA. DecompositionB. SynthesisC. Singe DisplacementD. Double DisplacementE. Combustion

Question 9

2Li2S + 2Cl2 -> 4LiCl + S2A. DecompositionB. SynthesisC. Singe DisplacementD. Double DisplacementE. Combustion

Question 10

2Fe + 6NaBr -> 2FeBr3 + 6NaA. DecompositionB. SynthesisC. Single DisplacementD. Double DisplacementE. Combustion

Question 11

CH4 + 2O2 -> Co2 +2H2OA. DecompositionB. SynthesisC. Single DisplacementD. Double DisplacementE. Combustion

Question 12

NaOH + KNO3 -> NaNO3 + KOHA. DecompositionB. SynthesisC. Single DisplacementD. Double DisplacementE. Combustion

Question 13

CaSO4 + Mg(OH)2 -> Ca(OH)2 + MgSO4A. DecompositionB. SynthesisC. Single DisplacementD. Double DisplacementE. Combustion

Question 14

2KClO3 -> 2KCl + 3O2A. DecompositionB. SynthesisC. Single DisplacementD. Double DisplacementE. Combustion

Question 15

Pb + O2 -> PbO2A. DecompositionB. SynthesisC. Single DisplacementD. Double DisplacementE. Combustion

Question 16

2Na + 2H2O -> 2NaOH + H2A. DecompositionB. SynthesisC. Single DisplacementD. Double DisplacementE. Combustion

Question 17

6CO2 + 6H2O ->C6H12O6 + 6O2A. DecompositionB. SynthesisC. Single DisplacementD. Double DisplacementE. Combustion

Question 18

HCl + NaOH -> NaCl + H2OA. DecompositionB. SynthesisC. Single DisplacementD. Double DisplacementE. Combustion