Elements A and B combine to form two different compounds. The first compound contains 15.0 grams of substance A, and 8.60 grams of substance B. It can be represented by the formula A2B (subscript 2). The second compound contains 5.0 grams of substance A, and 4.30 grams of substance B. What is the formula of the second compound?

To determine the formula of the second compound, we need to analyze the given masses of substances A and B.

Let's start by finding the molar masses of substances A and B. The molar mass of a substance is the mass of one mole of that substance, and it is expressed in grams per mole (g/mol). You can find the molar mass of an element on the periodic table.

Assuming that substance A corresponds to element A and substance B corresponds to element B:

Molar mass of A = Mass of A / Moles of A
Molar mass of B = Mass of B / Moles of B

Given the masses of substances A and B in the first and second compounds, we can calculate the moles of A and B in each compound using the respective molar masses.

First compound:
Moles of A in first compound = Mass of A in first compound / Molar mass of A
Moles of B in first compound = Mass of B in first compound / Molar mass of B

Second compound:
Moles of A in second compound = Mass of A in second compound / Molar mass of A
Moles of B in second compound = Mass of B in second compound / Molar mass of B

Next, we need to determine the ratio of moles of A to moles of B in each compound. To find the simplest ratio, we can divide the number of moles of each element by the smallest number of moles.

First compound ratio = (Moles of A in first compound) / (Moles of B in first compound)
Second compound ratio = (Moles of A in second compound) / (Moles of B in second compound)

Now, let's compare the ratios obtained for the first and second compounds.

If the two compounds have the same formula, A2B, the ratios (A-to-B ratio) should be equal.

First compound A-to-B ratio = First compound ratio
Second compound A-to-B ratio = Second compound ratio

If the A-to-B ratios of the two compounds are equal, then the formula of the second compound is also A2B. Otherwise, we need to simplify the ratio to determine the formula of the second compound.