How many grams of aluminum are in 25.0 g of aluminum oxide?

Explanation:

First we have to find the molar mass of the compound.

We must multiply the atomic mass of each element of the compound by the number of atoms of each one

Aluminum oxide:

molar mass

We know that in 1 mol of it has a mass of 101.96g.

Now we can find out how many moles of are in 25 g.

For every mole of we have 2 moles of Al.

To find out how many moles of Al we have in we use a rule of three

There are 0.49 moles of Al in 25 g of

now we calculate the grams of Al in 0.49 moles of Al

2fe + 3h2so4 -> fe2(so4)3 + 3h2

it is necessary to balance equations in order to get the proper amount of reactants as well as products in order not to make a miscalculation.

you cannot change the subscripts as that would change the substance itself. for instance, diatomic elements such as h2 only have the subscript two when a gas. another example would be so4, if you were to change the subscript, the element would no longer be sulfate.

we change the coefficients instead as that only changes the number of molecules rather than the substance itself.

hope this !