Question

27 gram of Al react completely with how much nass of o2 to produce Al2o3

Answer 1

the balanced reaction  in between Al and O2 is as follows:  

4Al + 3O₂ -----→ 2Al₂O₃

given that amount of Al = 27 g

number of moles = amount in g / molar mass

= 27 g/ 26.98 g/ mole  

= 1 .00  moles Al

Now calculate the mole of O2:

1 .00  moles Al * 3 mole O2/ 4 mole Al

= 0.75 mole O2

Amount of O2 = Number of moles * molar mass

= 0.75 mole *32 g/ mole

= 24 g O2