5.1 Exothermic and endothermic reactions

Cards (94)

What is the definition of an exothermic reaction?
Releases heat to surroundings
Exothermic reactions result in a net decrease in chemical energy. 
True
What is an example of an endothermic reaction?
Photosynthesis
Exothermic reactions have lower energy reactants than products. 
True
Why do exothermic reactions cause the temperature of the surroundings to increase?
They release thermal energy
Endothermic reactions involve a net increase in the chemical energy of the reactants.
True
In endothermic reactions, the temperature of the surroundings decreases
Order the key differences between exothermic and endothermic reactions based on energy changes:
1️⃣ Exothermic reactions release heat, causing the temperature to increase.
2️⃣ Endothermic reactions absorb heat, causing the temperature to decrease.
3️⃣ Exothermic reactions have a net decrease in chemical energy.
4️⃣ Endothermic reactions require an input of energy.
What type of energy is released during combustion reactions?
Thermal and light
Melting ice is an example of an endothermic reaction. 
True
What happens to heat flow in an exothermic reaction?
Releases heat to surroundings
Exothermic reactions result in a net decrease in chemical energy
Endothermic reactions require an input of energy to proceed. 
True
In endothermic reactions, energy is absorbed to break chemical bonds
Endothermic reactions require an input of energy to break bonds in the reactants. 
True
What type of energy is released during the combustion of wood?
Heat and light
An endothermic reaction absorbs heat from the surroundings
Match the exothermic reaction with its example:
Combustion ↔️ Burning wood
Neutralization ↔️ Mixing an acid and a base
Chemical release of energy ↔️ Sodium and chlorine reaction
In exothermic reactions, enthalpy changes are always negative
Match the reaction type with its effect on temperature:
Exothermic ↔️ Increase
Endothermic ↔️ Decrease
Endothermic reactions absorb heat to break bonds in the reactants.
What happens to the heat flow in exothermic reactions?
Heat is released
Exothermic reactions require an input of energy to proceed.
False
Match the reaction type with its example:
Exothermic ↔️ Combustion of methane
Endothermic ↔️ Dissolving potassium nitrate in water
Plants use light energy during photosynthesis to convert carbon dioxide and water into glucose and oxygen.
Match the characteristic with the reaction type:
Releases heat ↔️ Exothermic
Absorbs heat ↔️ Endothermic
In an exothermic reaction, the temperature increases. 
True
What is the primary effect of an endothermic reaction on the surroundings?
Temperature decreases
What is the net decrease in chemical energy in an exothermic reaction converted into?
Thermal energy
Exothermic reactions release heat to the surroundings
Match the reaction type with an example:
Combustion ↔️ Burning of wood
Neutralization ↔️ Mixing acid and base
Chemical Reaction ↔️ Na + Cl → NaCl
Melting ice is an example of an endothermic reaction. 
True
How does the chemical energy change in an exothermic reaction?
Net decrease
Match the characteristic with the correct reaction type:
Bond changes | Bonds form ↔️ Exothermic
Bond changes | Bonds break ↔️ Endothermic
Endothermic reactions require energy to break bonds in the reactants. 
True
In an exothermic reaction, the net decrease in chemical energy is converted into thermal energy
What is the thermal energy released in an exothermic reaction used for?
To increase the temperature
Steps in comparing exothermic and endothermic reactions based on energy changes
1️⃣ Identify the initial energy level of reactants
2️⃣ Determine the final energy level of products
3️⃣ Calculate the net energy change
4️⃣ Classify the reaction as exothermic or endothermic
Exothermic reactions release heat to the surroundings, while endothermic reactions absorb heat
Endothermic reactions require energy to break bonds in the reactants. 
True