#1: 2h2o + 2k (s) 2koh (l) + 2h2 (g) is an example of which type of reaction?
a. single-displacement
b. combustion
c. decomposition
d. double-displacement

D) double-displacement

Explanation:

In a displacement reaction, one or more atoms replace one or more atoms of a given molecule to form a new one.

In this case, two atoms of K replace two atoms of H in the water molecules two form H2 and KOH.

Is double because two displacement happen in the global reaction equation.  

the potential energy of the reactants is 200j.

from the energy diagram, the energy of the product formed is 350j; this means that, this reaction is an endothermic reaction, because it absorbs energy from its environment.

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