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Ch.8 - Basic Concepts of Chemical Bonding
All textbooksBrown 14th EditionCh.8 - Basic Concepts of Chemical BondingProblem 103
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Chapter 8, Problem 103

The compound chloral hydrate, known in detective stories as knockout drops, is composed of 14.52% C, 1.83% H, 64.30% Cl, and 13.35% O by mass, and has a molar mass of 165.4 g/mol. (c) Draw the Lewis structure of the molecule, assuming that the Cl atoms bond to a single C atom and that there are a C–C bond and two C–O bonds in the compound.

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Step 1: Determine the empirical formula of chloral hydrate using the given mass percentages. Assume a 100 g sample, which gives 14.52 g C, 1.83 g H, 64.30 g Cl, and 13.35 g O. Convert these masses to moles by dividing by their respective atomic masses: C (12.01 g/mol), H (1.008 g/mol), Cl (35.45 g/mol), and O (16.00 g/mol).
Step 2: Calculate the mole ratio of each element by dividing the number of moles of each element by the smallest number of moles calculated in Step 1. This will give you the simplest whole number ratio of atoms in the compound, which is the empirical formula.
Step 3: Determine the molecular formula by comparing the molar mass of the empirical formula to the given molar mass of the compound (165.4 g/mol). Multiply the subscripts in the empirical formula by a whole number to match the molar mass of the compound.
Step 4: Using the molecular formula, draw the Lewis structure. Start by arranging the atoms according to the given bonding information: Cl atoms bond to a single C atom, and there are a C–C bond and two C–O bonds. Place the remaining H and O atoms to satisfy the valency of each atom.
Step 5: Complete the Lewis structure by adding lone pairs to satisfy the octet rule for each atom, especially the oxygen and chlorine atoms. Ensure that the total number of valence electrons used in the structure equals the sum of the valence electrons from all atoms in the molecular formula.
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Textbook Question

One scale for electronegativity is based on the concept that the electronegativity of any atom is proportional to the ionization energy of the atom minus its electron affinity: electronegativity = k1I - EA2, where k is a proportionality constant. (b) Why are both ionization energy and electron affinity relevant to the notion of electronegativity?

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Textbook Question

One scale for electronegativity is based on the concept that the electronegativity of any atom is proportional to the ionization energy of the atom minus its electron affinity: electronegativity = k1I - EA2, where k is a proportionality constant. (c) By using data in Chapter 7, determine the value of k that would lead to an electronegativity of 4.0 for F under this definition.

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Textbook Question

One scale for electronegativity is based on the concept that the electronegativity of any atom is proportional to the ionization energy of the atom minus its electron affinity: electronegativity = k1I - EA2, where k is a proportionality constant. (d) Use your result from part (c) to determine the electronegativities of Cl and O using this scale. Use your result to determine the electronegativity of Cl using this scale.

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Open Question
Potassium peroxide is composed of 70.96% K and 29.04% O. Each peroxide ion has a net charge of 2-. (a) Given the molecular weight of the compound is 110.19, determine the chemical formula of potassium peroxide.
Textbook Question

Acetylene (C2H2) and nitrogen (N2) both contain a triple bond, but they differ greatly in their chemical properties. (b) By referring to Appendix C, look up the enthalpies of formation of acetylene and nitrogen. Which compound is more stable?

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Textbook Question

Under special conditions, sulfur reacts with anhydrous liquid ammonia to form a binary compound of sulfur and nitrogen. The compound is found to consist of 69.6% S and 30.4% N. Measurements of its molecular mass yield a value of 184.3 g/mol. The compound occasionally detonates on being struck or when heated rapidly. The sulfur and nitrogen atoms of the molecule are joined in a ring. All the bonds in the ring are of the same length. (a) Calculate the empirical and molecular formulas for the substance.

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