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WorksheetsExploring Energy in Chemical Reactions
Total questions: 15
Worksheet time: 8mins
Define an endothermic reaction.
An endothermic reaction is a reaction that absorbs heat.
An endothermic reaction is a process that generates energy.
An endothermic reaction releases heat.
An endothermic reaction occurs without any heat exchange.
Define an exothermic reaction.
An exothermic reaction is a reaction that releases energy, usually in the form of heat.
An exothermic reaction is a process that does not involve heat.
An exothermic reaction occurs only in gases.
An exothermic reaction absorbs energy from the surroundings.
Label the axes of an energy diagram for a reaction.
x-axis: Reaction Coordinate, y-axis: Energy
x-axis: Time, y-axis: Volume
x-axis: Temperature, y-axis: Pressure
x-axis: Concentration, y-axis: Mass
What does the peak of the energy diagram represent?
The transition state of a reaction.
The reactants of a reaction.
The products of a reaction.
The activation energy required for a reaction.
How do you calculate the enthalpy change (ΔH) for a reaction?
ΔH = H(products) + H(reactants)
ΔH = H(reactants) - H(products)
ΔH = ΣH(products) - ΣH(reactants)
ΔH = H(products) * H(reactants)
What is the enthalpy change for the reaction: A + B → C + 100 kJ?
-100 kJ
50 kJ
0 kJ
-200 kJ
Provide an example of an endothermic reaction.
Dissolution of ammonium nitrate in water
Formation of water from hydrogen and oxygen
Dissolution of sodium chloride in water
Combustion of methane
Provide an example of an exothermic reaction.
Photosynthesis (6CO2 + 6H2O -> C6H12O6 + 6O2)
Dissolving ammonium nitrate in water
Electrolysis of water (2H2O -> 2H2 + O2)
Combustion of methane (CH4 + 2O2 -> CO2 + 2H2O)
What is the significance of the activation energy in a reaction?
Activation energy is only relevant in biological reactions.
Activation energy determines the color of the reaction.
Activation energy has no effect on the stability of reactants.
Activation energy is significant because it influences the rate of a chemical reaction.
How does temperature affect endothermic and exothermic reactions?
Higher temperatures slow down both endothermic and exothermic reactions.
Temperature has no effect on either type of reaction.
Increasing temperature favors exothermic reactions and disfavors endothermic reactions.
Increasing temperature favors endothermic reactions and disfavors exothermic reactions.
In an exothermic reaction, what happens to the energy of the system?
The energy of the system decreases.
The energy of the system increases.
The energy of the system remains constant.
The energy of the system fluctuates.
What is the enthalpy change for the reaction: D + E → F - 50 kJ?
-25 kJ
-50 kJ
+50 kJ
0 kJ
Describe how energy diagrams differ for endothermic and exothermic reactions.
Endothermic reactions absorb energy, resulting in higher product energy; exothermic reactions release energy, resulting in lower product energy.
Both reactions have the same energy level for products and reactants.
Endothermic reactions release energy, resulting in lower product energy.
Exothermic reactions absorb energy, resulting in higher product energy.
What role do catalysts play in energy changes during reactions?
Catalysts increase activation energy, slowing down reactions.
Catalysts are consumed in the reaction, affecting energy changes.
Catalysts lower activation energy, speeding up reactions without altering overall energy changes.
Catalysts change the overall energy of the reaction.
Explain why photosynthesis is considered an endothermic process.
Photosynthesis releases energy as it converts glucose into carbon dioxide and water.
Photosynthesis occurs only at night when there is no sunlight.
Photosynthesis is an exothermic process that generates heat from sunlight.
Photosynthesis is an endothermic process because it absorbs energy from sunlight to convert carbon dioxide and water into glucose.
