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The empirical formula of a compound gives the simplest whole-number ratio of the elements present in the compound. To find the empirical formula, start by determining the mass of each element if you assume a 100g sample. For naphthalene, which is 93.71% carbon by mass, this means you have 93.71g of carbon and the remaining 6.29g is hydrogen (100% - 93.71%).
Convert these masses to moles by dividing each by the element's molar mass: for carbon it's 12.01 g/mol, and for hydrogen, it鈥檚 1.01 g/mol. This calculation gives 7.80 moles of carbon and 6.23 moles of hydrogen.
Next, derive the simplest ratio by dividing each mole value by the smallest number of moles calculated. Here, 6.23 is the baseline, leading to a ratio of approximately 1.25:1. However, chemical formulas use whole numbers, so multiply these ratios to get a whole number. Multiplying by 4 gives a ratio of C鈧匟鈧�, but real data shows C鈧佲個H鈧� is more accurate in practice.

The Ideal Gas Law connects pressure, volume, temperature, and the number of moles of a gas in a single equation: \( PV = nRT \). This equation is particularly useful for calculating properties of gases under certain conditions.
- **P** stands for pressure (in atmospheres, atm)- **V** is the volume (in liters, L)- **n** is the number of moles- **R** is the ideal gas constant, 0.0821 L路atm/mol路K- **T** is the temperature (in Kelvin, K)
For example, suppose you want to find the initial pressure of naphthalene gas. Convert 3.00g of naphthalene to moles using its molar mass, divide by volume (5.00L) and multiply by the gas constant and temperature (298K).
The answer provides the initial pressure in atm, which is crucial for further equilibrium calculations.

Percent sublimated refers to how much of a solid substance has turned into gas. This is important in understanding the behavior of compounds like naphthalene, which sublimates readily at room temperature.
To calculate the percentage sublimated, you need the amount of naphthalene that has escaped into the gas phase at equilibrium. This mass is determined using both the Ideal Gas Law and the equilibrium pressure. Subtract this mass from the initial mass and divide by the initial mass, then multiply by 100 to express as a percentage.
In our problem, 0.962 grams has sublimated from the initial 3.00 grams, leading to a 32.1% sublimation. This percentage helps illustrate how much of the naphthalene has transformed from solid to gas under given conditions.

The equilibrium constant \( K \) for a reaction represents the ratio of the concentrations of products to reactants at equilibrium. For naphthalene's sublimation, the constant is given as \( 4.29 \times 10^{-6} \) at 298K. This low value signifies that at equilibrium, very little naphthalene is in the gas phase under these conditions.
When dealing with gaseous equilibria, this constant lets you determine the pressures of the gases involved once equilibrium is reached. This is pivotal when calculating how much naphthalene sublimates into a closed space.
Having such a low equilibrium constant implies that the pressure of the gas is also low, confirming that naphthalene prefers remaining in solid form at room temperature unless specific conditions drive a significant phase change.