Energy Changes in Reactions

What is an example of an exothermic reaction?

• Combustion of hydrocarbons (e.g., burning wood or gasoline)

• Rusting of iron

• Dissolving salt in water

• Photosynthesis in plants

What is an example of an endothermic reaction?

• Combustion of gasoline

• Dissolving salt in water

• Photosynthesis

• Rusting of iron

Define bond breaking energy.

• Bond breaking energy refers to the temperature at which a bond can be broken.

• Bond breaking energy is the energy released when a chemical bond forms.

• Bond breaking energy is the energy required to create a chemical bond between atoms.

• Bond breaking energy is the energy needed to break a chemical bond between atoms.

Define bond making energy.

• Bond making energy refers to the total energy of a molecule.

• Bond making energy is the energy absorbed during the breaking of a chemical bond.

• Bond making energy is the energy released during the formation of a chemical bond.

• Bond making energy is the energy required to separate two bonded atoms.

What happens to energy during an exothermic reaction?

• Energy remains constant throughout the reaction.

• Energy is converted into mass.

• Energy is absorbed from the surroundings.

• Energy is released into the surroundings.

What happens to energy during an endothermic reaction?

• Energy is absorbed from the surroundings.

• Energy remains constant throughout the reaction.

• Energy is released into the surroundings.

• Energy is converted into mass.

What is the role of activation energy in reactions?

• Activation energy is crucial for initiating reactions by providing the energy needed for reactants to collide and form products.

• Activation energy is the energy released when products form.

• Activation energy is only relevant in exothermic reactions.

• Activation energy decreases the speed of reactions.

How do you determine if a reaction is exothermic or endothermic?

• A reaction is exothermic if it releases heat and endothermic if it absorbs heat.

• A reaction is exothermic if it produces light and endothermic if it produces sound.

• Exothermic reactions always occur at low temperatures, while endothermic reactions occur at high temperatures.

• A reaction is exothermic if it absorbs heat and endothermic if it releases heat.

What is the relationship between bond strength and energy changes?

• Stronger bonds correlate with greater energy changes during bond formation and breaking.

• Energy changes are unrelated to the type of bonds formed.

• Weaker bonds release more energy during formation.

• Bond strength has no effect on energy changes.

Give an example of a reaction that absorbs heat.

• Combustion

• Photosynthesis

• Respiration

• Decomposition