Exothermic & Endothermic Reactions

In an exothermic reaction, heat is ...

• Released

• Absorbed

• Synthsized

• Decomposed

The value of ΔH for an exothermic reaction is always...

• Positive

• Either positive or negative

• Negative

• 0

The chemical reaction 2H₂O --> 2H₂ +O₂ shows what process?

• Bond Making

• Bond Breaking

• Bond Forming

• Bond Togetherness

To calculate ΔH we use the formula

ΔH = Bond Energy of Reactants - Bond Energy of Products

If the energy of reactants is 450kJ and the Energy of the products is 600 kJ, what is the value of ΔH and is the reaction exothermic or endothermic?

• 150 Endothermic

• -150 Exothermic

• -150 Endothermic

• 150 Exothermic

You are in the lab reacting calcium chloride and water. You experience an exothermic reaction as heat is being released from the system. Which potential energy diagram best illustrates this exothermic reaction?

• A

• B

Which of the following is true about endothermic reactions?

• Heat is released

• The reaction feels warm/hot

• Heat is absorbed

You are in the lab and you react ammonium nitrate and water. Your observe that the reaction is cold. Which best describes the type of reaction between ammonium nitrate and water?

• Exothermic Reaction

• Combustion Reaction

• Unidentifiable Reaction

• Endothermic Reaction

Based on the following Energy Diagram, which statement best describes this image?

• The reaction is endothermic because the heat energy of the reactants is less the energy in the products. This means heat is absorbed in the reaction.

• The reaction is endothermic because the heat energy of the reactants is greater the energy in the products. This means heat is released in the reaction.

• The reaction is exothermic because the heat energy of the reactants is less the energy in the products. This means heat is absorbed in the reaction.

• The reaction is exothermic because the heat energy of the reactants is greater the energy in the products. This means heat is released in the reaction.