WorksheetsUnderstanding Reactions: Heat Changes
Total questions: 10
Worksheet time: 5mins
What is an endothermic reaction?
A reaction that occurs without any temperature change.
A reaction that only happens in the presence of a catalyst.
An endothermic reaction is a reaction that absorbs heat.
A reaction that releases heat.
What is an exothermic reaction?
An exothermic reaction absorbs energy from the surroundings.
An exothermic reaction occurs only in gases.
An exothermic reaction is a type of chemical reaction that does not involve heat.
An exothermic reaction is a reaction that releases energy, usually in the form of heat.
Give 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
Give an example of an exothermic reaction.
Rusting of iron (4Fe + 3O2 + 6H2O -> 4Fe(OH)3)
Dissolving ammonium nitrate in water
Combustion of methane (CH4 + 2O2 -> CO2 + 2H2O + heat)
Photosynthesis (6CO2 + 6H2O -> C6H12O6 + 6O2)
How do endothermic reactions affect temperature?
Endothermic reactions increase the temperature of their surroundings.
Endothermic reactions lower the temperature of their surroundings.
Endothermic reactions cause a rapid rise in temperature.
Endothermic reactions have no effect on temperature.
How do exothermic reactions affect temperature?
Exothermic reactions decrease the temperature of their surroundings.
Exothermic reactions only affect the temperature of the reactants.
Exothermic reactions have no effect on temperature.
Exothermic reactions increase the temperature of their surroundings.
What is the role of energy in chemical reactions?
Energy is irrelevant to the formation of products in chemical reactions.
Energy is essential for breaking bonds in reactants and forming new bonds in products during chemical reactions.
Energy acts as a catalyst that speeds up reactions without being consumed.
Energy is only needed for physical changes, not chemical reactions.
What is the difference between heat and temperature?
Temperature measures energy transfer.
Heat is a type of temperature.
Heat is energy transfer; temperature is a measure of thermal energy.
Heat is the same as temperature.
Can a reaction be both endothermic and exothermic?
Some reactions can switch between endothermic and exothermic phases.
Endothermic reactions can release energy in specific environments.
Yes, a reaction can be both endothermic and exothermic under certain conditions.
No, a reaction cannot be both endothermic and exothermic.
How can you identify if a reaction is endothermic or exothermic?
A reaction is endothermic if it absorbs heat (surroundings cool down) and exothermic if it releases heat (surroundings heat up).
A reaction is endothermic if it releases heat and exothermic if it absorbs heat.
A reaction is exothermic if it causes the temperature of the surroundings to drop.
Endothermic reactions always produce light and exothermic reactions do not.
