The following reactant molecules are rearranged to form the product molecules shown. The relevant bond enthalpies are given, in kJ/mol. What is the estimated enthalpy change for this reaction?

A. 678 kJ/mol
B. 198 kJ/mol
C. –265 kJ/mol
D. –632 kJ/mol

The population of unionid mussels decreased after zebra mussels were introduced. zebra mussels competed with the unionid mussels for food. the zebra mussels were able to displace the unionid mussels, allowing the zebra mussel population to increase  over the years. the unionid mussel population decreased because  of lack of food.

The answer is d for this question

If each of the reactants have 2 elements it is usually double displacement. when there is double displacement, if one reactant has hydrogen then it can be acid base. if one reactant has 2 and one has 1, than it is usually single displacement. if there is only one reactant it is decomposition. if there are two reactants that each have one element it is synthesis. if one of the reactants is 02 it can be combustion and the products has to include h20 and c02.