Energy Transformations in Exothermic and Endothermic Reactions

This video tutorial from freesciencelessons.co.uk covers the concepts of exothermic and endothermic reactions. It explains how exothermic reactions release energy to the surroundings, increasing the temperature, with examples like combustion and oxidation. Endothermic reactions, on the other hand, absorb energy, decreasing the temperature, with thermal decomposition as an example. The video also discusses energy profile diagrams and the concept of activation energy, which is the minimum energy required for particles to react. Practical applications of these reactions, such as in hand warmers and self-heating cans, are also highlighted.

What is the main characteristic of an exothermic reaction?

• It does not involve any energy change.

• It releases energy to the surroundings.

• It only occurs at high temperatures.

• It absorbs energy from the surroundings.

Which of the following is an example of an exothermic reaction?

• Evaporation

• Melting ice

• Combustion

• Photosynthesis

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

• Products and reactants have the same energy.

• Products have less energy than reactants.

• Products have more energy than reactants.

• Energy levels are not shown in the profile.

Which of the following is a common use of exothermic reactions?

• Refrigerators

• Hand warmers

• Cooling packs

• Air conditioners

What happens to the temperature of the surroundings during an endothermic reaction?

• It increases.

• It fluctuates randomly.

• It decreases.

• It remains constant.

Which of the following is an example of an endothermic reaction?

• Neutralization

• Combustion

• Thermal decomposition

• Oxidation

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

• Products and reactants have the same energy.

• Energy levels are not shown in the profile.

• Products have more energy than reactants.

• Products have less energy than reactants.

What is the term for the minimum energy required for a reaction to occur?

• Potential energy

• Thermal energy

• Kinetic energy

• Activation energy

Where is the activation energy represented on an energy profile diagram?

• From the peak of the curve to the surroundings

• From the products to the peak of the curve

• From the reactants to the peak of the curve

• From the reactants to the products

What must particles do to initiate a reaction?

• Absorb light

• Stay stationary

• Move randomly

• Collide with sufficient energy