What is the difference between isotopy and isotopes

 An isotope of different atoms in an element having the same atomic number but different mass numbers, whereas Isotope is of two forms, stable or unstable; on the other hand, the radioisotope is of only one form, which is an unstable isotope.

Explanation:

Isotopy is in the singular form and Isotopes is in the plural form

"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"

can you list the answers so i can answer