How many moles of potassium oxide will be formed when 1.52 moles of potassium reacts with oxygen according to the following equation:
4k + o2 -> 2k2o

0.76 mol.

Explanation:

4.0 moles of K will produce → 2.0 moles of K₂O.

1.52 moles of K will produce → ??? moles of K₂O.

∴ The no. of moles of potassium oxide will be formed when 1.52 moles of potassium reacts with oxygen = (1.52 mol)(2.0 mol)/(4.0 mol) = 0.76 mol.

"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"