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. (b) Write Lewis structures for the molecule, based on the information you are given. (Hint: You should find a relatively small number of dominant Lewis structures.)

Verified step by step guidance

1. Step 1: Determine the empirical formula of the compound. Start by assuming you have 100 g of the compound, which means you have 69.6 g of sulfur (S) and 30.4 g of nitrogen (N). Convert these masses to moles using their respective molar masses: S (32.07 g/mol) and N (14.01 g/mol).
2. Step 2: Calculate the mole ratio of sulfur to nitrogen 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 S to N, which is the empirical formula.
3. Step 3: Determine the molecular formula using the empirical formula and the given molecular mass of 184.3 g/mol. Calculate the molar mass of the empirical formula and divide the molecular mass by this value to find the multiplier needed to convert the empirical formula to the molecular formula.
4. Step 4: Draw the Lewis structure for the molecular formula. Since the problem states that the sulfur and nitrogen atoms form a ring and all bonds are of the same length, consider a symmetrical ring structure. Distribute the electrons to satisfy the octet rule for each atom, keeping in mind the total number of valence electrons available.
5. Step 5: Evaluate possible resonance structures. Since the problem hints at a small number of dominant Lewis structures, consider any resonance that might occur due to the symmetrical nature of the ring and the equal bond lengths. Ensure that all resonance structures obey the rules of formal charge minimization and octet completion.

Key Concepts

Molecular Composition and Percent Composition

Understanding the molecular composition involves analyzing the percentage of each element in a compound. In this case, the compound consists of 69.6% sulfur (S) and 30.4% nitrogen (N). This information is crucial for determining the empirical formula and ultimately the molecular formula, which can be derived from the molecular mass provided.

Molecular Mass and Molar Mass

Molecular mass refers to the mass of a single molecule of a substance, calculated by summing the atomic masses of all atoms in the molecule. The given molecular mass of 184.3 g/mol helps in identifying the molecular formula of the compound. By comparing the empirical formula mass with the molecular mass, one can determine the ratio of the empirical formula to the molecular formula.

Lewis Structures and Resonance

Lewis structures are diagrams that represent the bonding between atoms in a molecule and the lone pairs of electrons. For the compound in question, drawing the Lewis structures will help visualize the arrangement of sulfur and nitrogen atoms in a ring, as well as the nature of the bonds. The mention of 'dominant Lewis structures' suggests that resonance may play a role, indicating that multiple valid structures can represent the same molecule, contributing to its stability and reactivity.