An unknown compound has the following chemical formula: where \( x \) stands for a whole number. Measurements also show that a certain sample of the unknown compound contains 4.2 mol of chlorine and 1.41 mol of aluminum. Write the complete chemical formula for the unknown compound.

To determine the complete chemical formula of the unknown compound, we need to find the ratio of the moles of chlorine (Cl) to the moles of aluminum (Al) in the sample. Given: - Moles of chlorine (Cl) = 4.2 mol - Moles of aluminum (Al) = 1.41 mol Next, we can find the ratio of the moles of chlorine to the moles of aluminum: \[ \text{Ratio of Cl to Al} = \frac{\text{moles of Cl}}{\text{moles of Al}} = \frac{4.2}{1.41} \] Calculating this ratio: \[ \frac{4.2}{1.41} \approx 2.976 \] To express this ratio in whole numbers, we can round it to the nearest whole number. Since 2.976 is very close to 3, we can say that the ratio of chlorine to aluminum is approximately 3:1. This means that for every 1 atom of aluminum, there are approximately 3 atoms of chlorine. Therefore, we can write the empirical formula of the compound as: \[ \text{AlCl}_3 \] Thus, the complete chemical formula for the unknown compound is: \[ \text{AlCl}_3 \]