Chapter 7 Chemical Reactions

Chapter 7 Chemical Reactions

​By Dr. Luis Bello

Previous...

Chapter 6

Chapter 6 Chemical Composition 

6.2 Counting Nails by the Pound 

6.3 Counting Atoms by the Gram 

6.4 Counting Molecules by the Gram 

6.5 Chemical Formulas as Conversion Factors 

6.6 Mass Percent Composition of Compounds 

6.7 Mass Percent Composition from a Chemical Formula 

6.8 Calculating Empirical Formulas for Compounds 

6.9 Calculating Molecular Formulas for Compounds 

Checking Comprehension

Multiple Choice

Calculate the molar mass of KOH.

• 28 g/mol

• 56 g/mol

• 84 g/mol

• 112 g/mol

Multiple Choice

What is the molar mass of Cl₂?

• 17 g/mol

• 35.5 g/mo;

• 71.0 g/mol

• 89 g/mol

Multiple Choice

The element Q and P combine to form a compound. Which of the statements is correct about the new compound QP?

• QP will have properties different from Q and P.

• QP will have properties similar from Q and P.

• QP will have properties similar to Q but not P.

• QP will have properties similar to P but not Q.

Multiple Choice

One molecule of chlorine (Cl₂) weighs

• 17 amu

• 71 amu

• 34 amu

• 35.5 g

• 71 g

Multiple Choice

*What is the total number of atoms contained in 80 grams of neon?

• 6.02 x 10²³

• 1.2 x 10²⁴

• 2.4 x 10²⁴

• 4.8 x 10²⁴

Multiple Choice

A formula that shows the smallest whole-number ratio of the elements of a compound.

• molecular formula
• molar mass
• mole
• empirical formula

Multiple Choice

What are the units for molar mass?

• grams

• amu

• liters

• grams/mole

Today...

Chapter 7- Chemical Reactions 

Chemical Reactions Topics

7.2 Evidence of a Chemical Reaction 

7.3 The Chemical Equation 

7.4 How to Write Balanced Chemical Equations 

7.5 Aqueous Solutions and Solubility: Compounds Dissolved in Water 

7.6 Precipitation Reactions: Reactions in Aqueous Solution That Form a Solid 

7.7 Writing Chemical Equations for Reactions in Solution: Molecular, Complete Ionic, and Net Ionic Equations 

7.8 Acid–Base and Gas Evolution Reactions 

7.9 Oxidation–Reduction Reactions 

7.10 Classifying Chemical Reactions 

Evidence of a Chemical Reaction

The Chemical Equation

How to Write Balanced Chemical Equations 

Multiple Choice

Which of the following equations are correctly balanced?

• 12CO₂ + H₂O ---> C₆H₁₂O₆ + O₂

• CO₂ + H₂O ---> 3C₆H₁₂O₆ + O₂

• CO₂ + 9H₂O ---> C₆H₁₂O₆ + O₂

• 6CO₂ + 6H₂O ---> C₆H₁₂O₆ + 6O₂

Multiple Choice

Balance this equation:

HgO ---> 2Hg + O₂

• It is balanced.

• 2HgO ---> 2Hg + O₂

• 2HgO ---> Hg + O₂

• HgO ---> Hg + 2O₂

Multiple Choice

How many HCl molecules do you need to balance this equation? 
Mg +  __HCl --->  MgCl₂ + H₂

• 1
• 2
• 3
• 4

Multiple Choice

Is this balanced?
Al + O₂ → 2Al₂O₃

• Yes
• No

Home

Open in new tab

Copy link

Aqueous Solutions and Solubility: Compounds Dissolved in Water 

Precipitation Reactions: Reactions in Aqueous Solution That Form a Solid 

Writing Chemical Equations for Reactions in Solution: Molecular, Complete Ionic, and Net Ionic Equations 

Multiple Choice

Which is the correct net ionic equation for the reaction of AgNO₃ and CaCl₂?

• Ca²⁺(aq) +  2Cl^- (aq) → CaCl(s)
• Ag⁺(aq)  +  Cl^- (aq) → AgCl(s)
• Ag +  Cl  →  AgCl
• Ag⁺  +  Ca²⁺   →Ag₂Ca (s)

Multiple Choice

What are the spectator ions in this reaction?
CuCl₂(aq) + NaOH(aq) → Cu(OH)₂(s) + NaCl(aq)
 

• Cu²⁺ and OH^1-
• Na²⁺ and Cl^2-
• Na¹⁺ and Cl^1-
• Na¹⁺ and OH^1-

Acid–Base and Gas Evolution Reactions 

Oxidation–Reduction Reactions 

Classifying Chemical Reactions 

Multiple Choice

Evidence of a chemical reactions is anything that shows -

• a new substance has formed

• a solid dissolved in a liquid

• interaction between 2 gases

• a change in the state of matter

Multiple Choice

Hydrogen peroxide breaks down to form water and oxygen gas. Which observation is evidence that a chemical reaction has occurred?

• The mass of the solution remains the same.
•  Phase changes are observed.
•  The color of the solution remains clear.
• The temperature of the solution increases. 

Multiple Choice

Which of the following examples shows that a chemical reaction has occurred? 

• A rock breaks into smaller pieces when it is struck with a hammer.
• Rust forms on a hammer that has been left outside to long. 
• A cup of water turns pink when a few drops of red food coloring are added. 
• A solid is formed when heat is removed from a sample of water. 

Multiple Choice

In a chemical reaction, everything to the right of the arrow is called ______________.

• Products

• Yields

• Molecules

• Reactants

Multiple Choice

In the equation,          2Mg + O₂ ---> 2MgO, which are the reactants?

• Mg and O
• MgO
• Mg and MgO
• O and MgO

Multiple Choice

The substances at the beginning of a chemical equation are called the ____

• product
• yield
• chemical symbol
• reactants

Multiple Choice

What type of chemical reaction is this one?

CUO + CO2 --> CuCO3

• Decomposition

• Combustion

• Synthesis

• Single Replacement

Multiple Choice

What type of reaction involves one element replacing another element in a compound?

• Single Replacement Reaction

• Double Replacement Reaction

• Synthesis Reaction

• Decomposition Reaction

Multiple Choice

What type of reaction involves the breaking down of a substance into simpler substances?

• Single Replacement Reaction

• Double Replacement Reaction

• Synthesis Reaction

• Decomposition Reaction

Multiple Choice

What reaction has the following general formula:
$$C_xH_y\ +\ O_2\ ->CO_{2\ }+\ H_2O$$  

• Combination

• Decomposition

• Single Replacement

• Double Replacement

• Combustion

Multiple Choice

What reaction has the following general formula:

A + B --> AB

• Combination

• Decomposition

• Single Replacement

• Double Replacement

• Combustion

Multiple Choice

What reaction has the following general formula:

AB --> A + B

• Combination

• Decomposition

• Single Replacement

• Double Replacement

• Combustion

Multiple Choice

What reaction has the following general formula:

AB --> A + B

• Combination

• Decomposition

• Single Replacement

• Double Replacement

• Combustion