Textbook Question
Determine the degree of unsaturation for hydrocarbons with the following molecular formulas:
c. C12H20
d. C40H56
1. A Review of General Chemistry
Degrees of Unsaturation
2:21 minutesProblem 4d,e
Textbook Question
For each of the following molecular formulas, determine the number of elements of unsaturation, and draw three examples.
d. C5H5NO2
e. C6H3NClBr
Verified step by step guidance1
Step 1: Understand the concept of elements of unsaturation. Elements of unsaturation, also known as degrees of unsaturation, refer to the number of π bonds and rings in a molecule. Each degree of unsaturation corresponds to either one ring or one double bond.
Step 2: Use the formula for calculating elements of unsaturation: \( ext{Degrees of Unsaturation} = rac{2C + 2 + N - H - X}{2} \), where \( C \) is the number of carbons, \( N \) is the number of nitrogens, \( H \) is the number of hydrogens, and \( X \) is the number of halogens (F, Cl, Br, I).
Step 3: Apply the formula to the molecular formula \( ext{C}_5 ext{H}_5 ext{NO}_2 \). Substitute the values into the formula: \( ext{Degrees of Unsaturation} = rac{2(5) + 2 + 1 - 5 - 0}{2} \). Calculate the result to find the degrees of unsaturation.
Step 4: Apply the formula to the molecular formula \( ext{C}_6 ext{H}_3 ext{NClBr} \). Substitute the values into the formula: \( ext{Degrees of Unsaturation} = rac{2(6) + 2 + 1 - 3 - 2}{2} \). Calculate the result to find the degrees of unsaturation.
Step 5: Draw three structural examples for each molecular formula that match the calculated degrees of unsaturation. Consider different combinations of rings and double bonds that satisfy the unsaturation number.
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Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Elements of Unsaturation
Elements of unsaturation, also known as degrees of unsaturation, refer to the number of pi bonds and rings in a molecule. It is calculated using the formula: (2C + 2 + N - H - X)/2, where C is the number of carbons, N is the number of nitrogens, H is the number of hydrogens, and X is the number of halogens. This concept helps in determining the structural possibilities of a given molecular formula.
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Molecular Formula Analysis
Analyzing a molecular formula involves understanding the composition and connectivity of atoms within a molecule. It requires identifying the types and numbers of atoms present, which aids in predicting possible structures and functional groups. This analysis is crucial for determining elements of unsaturation and drawing structural examples.
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Drawing Structural Isomers
Structural isomers are different compounds with the same molecular formula but different connectivity of atoms. Drawing structural isomers involves creatively arranging atoms to form distinct structures, considering elements of unsaturation and functional groups. This skill is essential for visualizing and representing the diversity of possible molecular structures.
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