During her science fair project, mary discovered that solutions of ionic compounds in water conduct electricity. what type of investigation could mary perform to discover which type of ions conduct electricity best?

Mary could do two types of experiments

Type 1. She could hold the cation constant and vary the anion.

She could try solutions of NaCl, NaBr, NaI, Na₂SO₄, Na₃PO₄, etc.

These experiments would tell her which anions are the best conductors.

Type 2. She could hold the anion constant and vary the cation.

She could try solutions of NaNO₃, KNO₃, Mg(NO₃)₂, Ca(NO₃)₂, Al(NO₃)₃, etc.

These experiments would tell her which cations are the best conductors.

"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"