Chapter 6- Chemical Composition

Chapter 6- Chemical Composition

​Presenter: Dr. Luis Bello

Previous Chapter

Chapter 5- Molecules and Compounds 

Topics from Chapter 5

• 5.2 Compounds Display Constant Composition  

  5.3 Chemical Formulas: How to Represent Compounds  

  5.4 A Molecular View of Elements and Compounds  

  5.5 Writing Formulas for Ionic Compounds  

  5.6 Nomenclature: Naming Compounds  

  5.7 Naming Ionic Compounds  

  5.8 Naming Molecular Compounds  

  5.9 Naming Acids  

  5.10 Nomenclature Summary  

  5.11 Formula Mass: The Mass of a Molecule or Formula Unit  

Checking Comprehension

Multiple Select

H₂0 - name?

• hydrooxic acid

• hydrogen oxygen

• water

• hydrogen oxide

Multiple Choice

What is the correct name for the compound with the formula NH₄NO₃

• ammonium nitrite

• ammonium nitrate

• ammonium nitride

Multiple Choice

What is the correct name for Mn(SO₄)₂

• Manganese (VI) Sulfate

• Manganese (IV) Sulfate

• Magnesium (II) Sulfide

• Magnesium (III) Sulfide

Multiple Choice

What is the correct formula for Calcium Phosphate?

• Ca₃(PO₄)₂

• Ca₃(PO₄)

• Ca₂(PO₄)

• Ca₂(PO₄)₂

Multiple Choice

LiOH- name?

• hydrogen lithium

• lithium oxyhydride

• lithium oxide

• lithium hydroxide

Multiple Choice

HCl- name?

• hydrogen chloride

• chlorine hydrogen

• hydrogen chlorine

• hydrogen chlorate

Multiple Choice

What is the correct name for MoO₃

_{(think about how compounds have to be reduced to the simplest integer ratio)}

• Molybdenum V oxide

• Molybdenum VI oxide

• Molybdenum III oxide

Multiple Choice

What is the correct name for the compound with the formula (NH₄)₃PO₄

• Ammonium Pyrophosphite

• Ammonium Phoporylate

• Ammonium Phosphite

• Ammonium Phosphate

Topics

• 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  

Mass Percent Composition of Compounds 

Another example

Calculating Empirical Formulas for Compounds  

Example

Multiple Choice

The empirical formula of a compound is CH₂O, and its mass is 120 amu/molecule. Calculate its molecular formula.

• C₃H₆O₃

• C₄H₈O₄

• C₂H₄O₂

• CH₂O

Multiple Choice

*Find the percent composition of N₂S₂.

• N: 69.6% S: 30.4%

• N:36% S: 75.6%

• N: 96.6% S: 3.4%

• N: 30.4% S: 69.6%

Multiple Choice

What is the percent by mass of sodium in NaCl?

• 39%
• 61%
• 35%
• 65%

Multiple Choice

What is the percent by mass of sodium in NaCl?

• 39%
• 61%
• 35%
• 65%

Multiple Choice

Which formula is an empirical formula?

• H₂O₂

• C₂H₆O₁₂

• CaCl₂

• N₂O₈

Multiple Choice

Which pair has the same empirical formula?

• NaCrO₄ and Na₂Cr₂O₇
• C₂H₄O₂ and C₆H₁₂O₆
• C₃H₆O₃ and C₂H₆O₂
• CH₄ and C₂H₆