Question

choose the words to finish the sentences.
the image shows the direction of heat flow for a reaction mixture in a laboratory environment.
lab environment
reaction
mixture
heat
the reaction mixture represents the choose... . based on the heat flow, one can conclude that the bond enthalpy of the products formed during the reaction is choose... the bond enthalpy of the reactants present at the beginning of the reaction.

Explanation:

Step1: Analyze the system (reaction mixture vs lab environment)

In thermodynamics, the reaction mixture is the system (the part we focus on), and the lab environment is the surroundings. So the first blank should be "system".

Step2: Analyze heat flow and bond enthalpy

Heat is flowing out of the reaction mixture (system) to the surroundings. This means the reaction is exothermic. For exothermic reactions, the total bond enthalpy of products is greater than that of reactants (because energy is released when products have stronger bonds, i.e., higher total bond enthalpy, than reactants).

Answer:

First blank: system
Second blank: greater than