Question

A compound made of two elements, iridium (Ir) and oxygen (O), was produced in a lab by heating iridium while exposed to air. The following data was collected:

Mass of crucible: 38.26 g
Mass of crucible and iridium: 39.52 g
Mass of crucible and iridium oxide: 39.73 g

Show, or explain, your calculations as you determine the empirical formula of the compound.

Answer 1

Well, to get the mass of the Ir, subtract the mass of the crucible.
Same with mass of Irid Oxide
To get the mass of oxygen subtract the mass of iridium from the mass of iridium oxide.
Now, you need to find the percent of each element in the compound. So, take the mass of each element and divide it by the total mass of the compound. (you should refer to your periodic table for this).
Next, change the percents over to grams and use the molar mass of each to get the moles of each in the compound.

You might notice that your value is a decimal, however, decimals CANNOT be your mole subscripts in your formula, hence you need to divide both numbers by the smaller of the two decimal values. And you should have whole number values. That should tell you the moles of each Ir and O

Answer 2

thank you