A compound composed of 6.7% H, 40.0% C, and 53.3% O has a molar mass of approximately 60 g>mol. (c) What is the geometry and hybridization of the C atom that is bonded to 2 O atoms?

Verified step by step guidance

Step 1: Determine the empirical formula of the compound. Start by assuming you have 100 g of the compound, which means you have 6.7 g of H, 40.0 g of C, and 53.3 g of O. Convert these masses to moles by dividing by their respective atomic masses: H (1.01 g/mol), C (12.01 g/mol), and O (16.00 g/mol).

Step 2: Calculate the mole ratio of the elements by dividing each element's mole value by the smallest number of moles calculated in Step 1. This will give you the simplest whole number ratio of the elements, which is the empirical formula.

Step 3: Determine the molecular formula. Use the empirical formula mass and compare it to the given molar mass of the compound (60 g/mol). Divide the molar mass by the empirical formula mass to find the multiplier needed to convert the empirical formula to the molecular formula.

Step 4: Identify the structure of the compound. Based on the molecular formula, consider possible structures that include a carbon atom bonded to two oxygen atoms. A common structure is the carboxyl group (-COOH), where the carbon is double-bonded to one oxygen and single-bonded to another oxygen (which is also bonded to hydrogen).

Step 5: Determine the geometry and hybridization of the carbon atom in the carboxyl group. The carbon atom in a carboxyl group is typically sp² hybridized, resulting in a trigonal planar geometry. This is due to the presence of three regions of electron density around the carbon atom (one double bond and two single bonds).

Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

Empirical and Molecular Formulas

To determine the molecular structure of a compound, one must first derive its empirical formula from the percentage composition of its elements. In this case, the percentages of hydrogen, carbon, and oxygen can be converted to moles, leading to a ratio that helps identify the simplest whole-number formula. The molar mass then allows for the calculation of the molecular formula, which is essential for understanding the compound's structure.

Hybridization

Hybridization is a concept that describes the mixing of atomic orbitals to form new hybrid orbitals, which can explain the geometry of molecular bonding. For carbon, common hybridizations include sp3, sp2, and sp, corresponding to different geometries such as tetrahedral, trigonal planar, and linear, respectively. The hybridization of the carbon atom bonded to two oxygen atoms can be determined by analyzing its bonding and the number of lone pairs present.

Molecular Geometry

Molecular geometry refers to the three-dimensional arrangement of atoms within a molecule, which is influenced by the number of bonding pairs and lone pairs of electrons around the central atom. The VSEPR (Valence Shell Electron Pair Repulsion) theory helps predict the geometry based on electron pair repulsion. In this case, understanding the geometry of the carbon atom bonded to two oxygen atoms is crucial for predicting the overall shape of the molecule.

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Textbook Question

The energy-level diagram in Figure 9.40 shows that the sideways overlap of a pair of p orbitals produces two molecular orbitals, one bonding and one antibonding. In ethylene there is a pair of electrons in the bonding orbital between the two carbons. Absorption of a photon of the appropriate wavelength can result in promotion of one of the bonding electrons from the to the molecular orbital. a. Assuming this electronic transition corresponds to the HOMO–LUMO transition, what is the HOMO in ethylene?

Textbook Question

The energy-level diagram in Figure 9.40 shows that the sideways overlap of a pair of p orbitals produces two molecular orbitals, one bonding and one antibonding. In ethylene there is a pair of electrons in the bonding orbital between the two carbons. Absorption of a photon of the appropriate wavelength can result in promotion of one of the bonding electrons from the to the molecular orbital. b. Assuming this electronic transition corresponds to the HOMO–LUMO transition, what is the LUMO in ethylene?

Textbook Question

The energy-level diagram in Figure 9.40 shows that the sideways overlap of a pair of p orbitals produces two molecular orbitals, one bonding and one antibonding. In ethylene there is a pair of electrons in the bonding orbital between the two carbons. Absorption of a photon of the appropriate wavelength can result in promotion of one of the bonding electrons from the to the molecular orbital. c. Is the bond in ethylene stronger or weaker in the excited state than in the ground state? Why?

Textbook Question

Sulfur tetrafluoride 1SF42 reacts slowly with O2 to form sulfur tetrafluoride monoxide 1OSF42 according to the following unbalanced reaction: SF41g2 + O21g2¡OSF41g2 The O atom and the four F atoms in OSF4 are bonded to a central S atom. (a) Balance the equation.

Textbook Question

Sulfur tetrafluoride (SF₄) reacts slowly with O₂ to form sulfur tetrafluoride monoxide (OSF₄) according to the following unbalanced reaction: SF₄(g) + O₂(g) → OSF₄(g) The O atom and the four F atoms in OSF₄ are bonded to a central S atom. (b) Write a Lewis structure of OSF₄ in which the formal charges of all atoms are zero.

Textbook Question

Sulfur tetrafluoride (SF₄) reacts slowly with O₂ to form sulfur tetrafluoride monoxide (OSF₄) according to the following unbalanced reaction: SF₄(g) + O₂(g) → OSF₄(g) The O atom and the four F atoms in OSF₄ are bonded to a central S atom. (c) Use average bond enthalpies (Table 8.3) to estimate the enthalpy of the reaction. Is it endothermic or exothermic?