Calculate the mass of iron (iii) oxide that contains a trillion iron atoms

Calculate the mass of iron(III) oxide (Fe20) that contains a trillion (1.000x 10") oxygen atoms. Be sure your answer has a unit symbol if necessary, and round it to 4 significant digits. A chemist measures the amount of oxygen gas produced during an experiment. He finds that 9.2 g of oxygen gas is produced.

Explanation:

do u have any choices to choose from ? ?

"you start with 15.67 g mgco3-xh2o, when heated and all the water is removed, you are left with 7.58 g mgco3 only.

therefore, you had 15.67 - 7.58 = 8.09g h2o  

moles of each :

7.58g mgco3 = ? moles = 7.58g / 83.4g/mole = 0.09moles  

8 09g h2o = ? moles = 8.09g / 18g/mole = 0.44moles  

molar ratio between the two by dividing both numbers by the smallest number :

0.09 / 0.09 = 1  

0.44 / 0.09 = 4.8  

mgco3-5h2o"