Question

how to set up or approach these

1. Calculate the mass in grams of iodine (I2) that will react completely with 48.9 g of aluminum (Al) to form aluminum iodide (AlI3).

Do I need to find the mass as a whole for the entire compound, then convert?

2. The formula for rust can be represented by Fe2O3. How many moles of Fe are present in 24.4 g of the compound

And I don't know how to get started on this one.

Answer 1

you have to go

mol=g/mm

mol=grams/molecular mass

to find how many moles are in Fe2O3

Answer 2

For the AlI3 question.
1.Writ the equation and balance it.
2.Convert 48.9 g Al to moles; moles = grams/atomic mass.
3.Using the coefficients in the balanced equation, convert moles Al to moles AlI3.
4.Convert moles AlI3 to grams. grams = moles x molar mass.
Post your work if you get stuck.

For the second part.
moles = grams/molar mass.