8. based on the formula, predict whether each of the following compounds is primarily ionic or primarily covalent. a. sodium iodide (nai) d. ammonia (nh3) b. methane (ch4) e. glucose (c6h12o6) c. calcium chloride (cacl2)

primarily ionic  include = sodium iodide( NaI) ,   calcium chloride  ( CaCl2)

primarily covalent    include  - Ammonia (NH3) , Methane ( CH4)  and  

                                                   Glucose  (C6H12O6)

Explanation

ionic  bond  is formed  when  there is complete transfer of electron between atoms. It occur  between metal  which  donate electrons and  a  non  metal which accept  electrons.

 for  example  in  formation  of CaCl2,   ca  donate  2 electron to 2  Cl atom, while  2 Cl atom accept the 2  electrons  to form ionic bond.

 Covalent bond  is formed  when two or  more  non  metal  form bond by sharing  electrons pairs.

For  example in NH3   3 pairs of electron are shared.  to form covalent bond.

answer: enthalpy

explanation:

for a exothermic reaction, the energy is released i.e. the energy of the products is lower than the energy of the reactants.

= enthaply

= energy of products

= energy of reactants

as , thus comes out to be negative. negative value of enthalpy shows that the reaction is exothermic.