GCSE Chemistry - Exothermic and Endothermic Reactions #43

The video tutorial explains exothermic and endothermic reactions, focusing on how energy is stored in chemical bonds and represented in reaction profiles. It discusses the importance of activation energy, illustrating how it affects the initiation of reactions. Examples of exothermic reactions, such as combustion, and endothermic reactions, like the breakdown of calcium carbonate, are provided. The tutorial also covers how to draw reaction profiles, highlighting the energy changes and activation energy involved.

What is the main factor that determines the energy stored in chemical bonds?

• The number of molecules

• The type of atoms involved

• The total energy of reactants and products

• The amount of energy in the surroundings

Which of the following is a characteristic of exothermic reactions?

• They release energy to the surroundings

• They decrease the temperature of the surroundings

• They require no activation energy

• They absorb energy from the surroundings

What is a common example of an exothermic reaction?

• Photosynthesis

• Combustion

• Melting ice

• Electrolysis

In an endothermic reaction, how do the energy levels of products compare to reactants?

• Products have less energy than reactants

• Energy levels are not comparable

• Products have the same energy as reactants

• Products have more energy than reactants

Which process is an example of an endothermic reaction?

• Combustion of methane

• Neutralization of an acid

• Photosynthesis

• Rusting of iron

What does activation energy represent in a chemical reaction?

• The total energy of the products

• The energy released during the reaction

• The energy absorbed by the reactants

• The energy required to start a reaction

How can activation energy be visualized on a reaction profile?

• As the difference in energy between reactants and products

• As the highest point on the energy curve

• As the lowest point on the energy curve

• As the total energy of the reactants