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Key Concepts PowerPoint

Chapter 3
Formulas, Equations, and Moles

 
03-00-02UN
Title
Balancing chemical equations
Caption
After writing the correct chemical formula for each reactant and product, balancing of the equation is then accomplished by placing coefficients in front of the appropriate chemical species. The coefficient 'multiplies' the number of each atom for a particular formula unit in order to balance the equation.
Notes
When a coefficient is not specifed for a particular species in an equation, the coefficient is assumed to be 1.
Keywords
reaction, equation, balancing, coefficients
03-00-03UN1
Title
Balancing equations
Caption
When balancing chemical equations, coefficients are added in front of a particular species indicating multiple numbers of a formula unit. Do not change subscripts found within a formula unit since this actually changes the identity of the intended reactant or product.
Notes
Proper placement of coefficients
Keywords
coefficients, equation, balancing
03-00-03UN2
Title
Comparison of water and hydrogen peroxide
Caption
Although these two molecules contain only hydrogen and oxygen, they are not the same compound.
Notes
Structures of water and hydrogen peroxide
Keywords
water, hydrogen peroxide
03-00-08UN
Title
Worked Key Concept Example 3.3
Caption
Write a balanced equation for the reaction between A (red spheres) and B (blue spheres) represented by the diagrams.
Notes
Worked Key Concept Example 3.3
Keywords
key concept, reaction, balancing
03-00-09UN
Title
Key Concept Problem 3.3
Caption
Write a balanced chemical equation for the reaction between A (red spheres) and B (green spheres) as represented in the diagrams.
Notes
Key Concept Problem 3.3
Keywords
key concept, reaction, balancing
03-00-10UN
Title
Formation of water
Caption
The space-filling models of hydrogen and oxygen are shown to react and produce two molecules of water. The reaction equation is balanced.
Notes
Formation of water
Keywords
water, equation
03-00-11UN
Title
Formation of ethyl chloride
Caption
The molecules of ethylene and hydrogen chloride react and combine to form a new compound, ethyl chloride, which is used as a topical anesthetic.
Notes
Formation of ethyl chloride, C2H5Cl
Keywords
ethyl chloride, reaction
03-01
Title
Relationship between mass and moles
Caption
Figure 3.1 (a) Because one gumdrop weighs more than one jellybean, you can’t get equal numbers merely by taking equal weights. The same is true for different atoms or molecules. (b) Equal numbers of HCl and ethylene molecules always have a mass ratio equal to the ratio of their molecular masses, 36.5 to 28.0.
Notes
Relationship between mass and moles
Keywords
mass, mole
03-01-03UN
Title
Formation of ammonia
Caption
Instead of representing the number of individual atoms or molecules of a reactant or product, the coefficients in a balanced chemical equation also represent the number of moles of a reactant or product.
Notes
Balanced equation for the industrial synthesis of ammonia—arrows pointing to moles of hydrogen, nitrogen, and ammonia
Keywords
mole, ammonia, equation
03-01-04UN
Title
Key Concept Problem 3.6
Caption
Using the structural model shown, what is the chemical formula and molecular mass of methionine (red = O, gray = C, blue = N, yellow = S, ivory = H)?
Notes
Key Concept Problem 3.6
Keywords
key concept, formula, mass
03-02
Title
Conversion between moles and mass
Caption
Figure 3.2 A summary of conversions between moles and grams for a chemical reaction. The numbers of moles tell how many molecules of each reactant are needed, as given by the balanced equation; the numbers of grams tell how much mass of each reactant is needed.
Notes
Conversion between moles and mass
Keywords
mole, mass, conversion
03-02-02UN
Title
Stiochiometry calculation
Caption
Solving stoichiometry problems first involves having a balanced chemical equation. Take the known mass of a chemical species and convert it to moles using molecular mass as a conversion factor. Use the ratio of the appropriate equation coefficients to convert moles of one species to moles of another species. Finally, use the molar mass of the latter species to convert moles into grams.
Notes
Worked Example 3.7
Keywords
stoichiometry, calculation, conversion
03-02-03UN
Title
Structure of aspirin
Caption
Aspirin has the molecular formula C9H8O4.
Notes
Structure can be used in conjunction with Problems 3.7 and 3.8
Keywords
aspirin
03-02-04UN
Title
Structure of methyl tert-butyl ether (MTBE)
Caption
Ball-and-stick model of MTBE, C5H12O.
Notes
Can be used in conjunction with Worked Example 3.8
Keywords
MTBE, ether
03-02-05UN
Title
Structure of diethyl ether
Caption
Ball-and-stick model of diethyl ether.
Notes
Can be used in conjunction with Worked Example 3.9
Keywords
diethyl ether, ether
03-02-07UN
Title
Formation of ethylene glycol
Caption
Although the reaction equation shows that only one mole of ethylene oxide reacts with one mole of water to produce ethylene glycol, it is often the case in the laboratory that reactants are not mixed in the same ratios as the equation dictates.
Notes
This example is meant to introduce the concept of 'limiting reactant' or 'limiting reagent'
Keywords
limiting reactant, ethylene glycol
03-02-08UN
Title
Effect of limiting reactant
Caption
If water is in excess with respect to the balanced chemical equation, then the moles of ethylene glycol formed is dependent on the moles of ethylene oxide used. Therefore, some water will be left unreacted when the reaction is complete.
Notes
Effect of limiting reactant
Keywords
limiting reactant, ethylene glycol
03-02-09UN
Title
Structure of cisplatin
Caption
Ball-and-stick model of cisplatin.
Notes
Can be used in conjunction with Worked Example 3.10
Keywords
cisplatin
03-02-10UN
Title
Balanced equation and limiting reactant
Caption
Key Concept Problem 3.13 Write a balanced equation for the reaction and identify the limiting reactant.
Notes
Key Concept Problem 3.13
Keywords
key concept, balanced equation, limiting reactant
03-05
Title
Molarity as a conversion factor
Caption
Figure 3.5 A flow diagram summarizing the use of molarity as a conversion factor between moles and volume in stoichiometry calculations.
Notes
Molarity as conversion factor
Keywords
molarity, conversion, mole, volume
03-06
Title
Acid-base titration
Caption
Figure 3.6 A flow diagram for an acid-base titration, summarizing the calculations needed to determine the concentration of an HCl solution by titration with an NaOH standard solution.
Notes
A flow diagram for an acid-base titration
Keywords
titration, stoichiometry
03-08
Title
Chemical formula from percent composition
Caption
Figure 3.8 A flow diagram for calculating the formula of a compound from its percent composition.
Notes
When only percent compositions of each element are given, assume you have 100.0 g of the compound and proceed with the calculations.
Keywords
percent composition, formula, empirical
03-08-01UN
Title
Structure of ascorbic acid (Vitamin C)
Caption
Ball-and-stick model of ascorbic acid.
Notes
Can be used in conjunction with Worked Example 3.15
Keywords
ascorbic acid, vitamin C
03-08-03UN
Title
Structure of glucose (blood sugar)
Caption
Ball-and-stick model of glucose, C6H12O6.
Notes
Can be used in conjunction with Worked Example 3.16
Keywords
glucose, blood sugar
03-09
Title
Empirical formula from combustion analysis
Caption
Figure 3.9 A flow diagram for determining an empirical formula from combustion analysis of a compound containing C and H.
Notes
Although the products carbon dioxide and water determine the number of moles of carbon and hydrogen in the sample, the number of moles of oxygen may need to be determined separately in order to account for the entire mass of the combusted sample.
Keywords
combustion, empirical formula
03-09-01UN
Title
Structure of naphthalene
Caption
Ball-and-stick model of naphthalene, C10H8.
Notes
Can be described as the primary ingredient to commercial moth balls (not to be confused with commercial moth crystals which are made from para-dichlorobenzene.
Keywords
naphthalene
03-09-02UN
Title
Structure of caproic acid
Caption
Ball-and-stick model of caproic acid.
Notes
Can be used in conjunction with Worked Example 3.18
Keywords
caproic acid
03-10
Title
Mass spectrometry
Caption
Figure 3.10 (a) Schematic of a mass spectrometer. Sample molecules are ionized by collision with a high-energy electron beam, and the resulting ions are then passed between the poles of a magnet, where they are deflected according to their mass-to-charge ratio. The deflected ions pass through a slit into a detector assembly. (b) A mass spectrum of naphthalene, molec. mass = 128, showing peaks of different masses on the horizontal axis.
Notes
Schematic of a mass spectrometer
Keywords
mass spectrometer, mass spectrometry molecular mass
03-10-02.1
Title
Key Concept Summary
Caption
Formulas, equations, and moles key concept summary.
Notes
Key Concept Summary for Chapter 3
Keywords
key concepts, summary
03-10-03UN
Title
Key Concept Problem 3.30
Caption
Diagram for Problem 3.30.
Notes
Key Concept Problem 3.30
Keywords
key concept, dilution
03-10-04UN
Title
Key Concept Problem 3.30
Caption
Reaction of A (green spheres) with B (blue spheres) is shown schematically in the following diagram:
Notes
Key Concept Problem 3.30
Keywords
key concept, stoichiometry
03-10-05UN
Title
Key Concept Problem 3.32
Caption
Structure of cytosine, a constituent of DNA.
Notes
Can be used in conjunction with Problem 3.32
Keywords
cytosine
03-10-06UN
Title
Key Concept Problem 3.33
Caption
Reaction between NO and O2 to produce NO2.
Notes
Key Concept Problem 3.33
Keywords
key concept, reactant, product
03-10-07
Title
Key Concept Problem 3.34
Caption
Structure of fluoxetine (Prozac) (red = O, blue = N, yellow-green = F, ivory = H).
Notes
Key Concept Problem 3.34
Keywords
fluoxetine, prozac
03-10-08UN
Title
Key Concept Problem 3.35
Caption
Acid-base titration.
Notes
Key Concept Problem 3.35
Keywords
key concept, titration
03-10-09
Title
Key Concept Problem 3.36
Caption
Red and blue spheres to represent reaction of A2 and B2.
Notes
Key Concept Problem 3.36
Keywords
key concept, limiting reactant
03-10-10UN
Title
Key Concept Problem 3.37
Caption
A hydrocarbon of unknown formula CxHy was submitted to combustion analysis.
Notes
Key Concept Problem 3.36
Keywords
key concept, empirical formula, combustion analysis

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