Final answer:
The mole ratio of chlorine to copper is 2:1 for the brown compound and 1:1 for the green compound, as indicated by atomic theory and confirmed by calculating the mass ratios from given data.
Step-by-step explanation:
To calculate the mole ratio of chlorine to copper, we can use the data provided on the two compounds formed by copper and chlorine. For compound A, which is the brown compound, the mole ratio of chlorine to copper comes from the atomic theory suggesting a 1:2 ratio of copper to chlorine atoms, resulting in a chlorine to copper mole ratio of 2:1. With compound B, the green compound, the atomic theory indicates a 1:1 ratio of copper to chlorine atoms, giving us a mole ratio of chlorine to copper of 1:1. The masses given for compound A are 4.08 g of copper and 2.28 g of chlorine and for compound B, 7.53 g of copper and 8.40 g of chlorine.
Applying the law of multiple proportions, for compound A, 7.53 g Cu / 8.40 g Cl = 0.896 g Cu/g Cl and for compound B, 4.08 g Cu / 2.28 g Cl = 1.79 g Cu/g Cl. Therefore, the lowest whole number mass ratio of copper that combines with a given mass of chlorine in compound A is approximately 1:2, confirming the 2-to-1 mole ratio provided by atomic theory.