What Are Endothermic & Exothermic Reactions | Chemistry | FuseSchool

Summary

This video script explores the concepts of exothermic and endothermic reactions, contrasting their energy transfer processes. Exothermic reactions release energy, causing surroundings to heat up, as seen in fires and neutralization reactions. Endothermic reactions absorb energy, cooling the surroundings, exemplified by melting and photosynthesis. The script simplifies these reactions using a thermometer to detect temperature changes and explains that exothermic processes start with higher energy and end with lower, while endothermic processes do the opposite. It concludes by noting that exothermic reactions are more common.

Takeaways

• 🔥 Exothermic reactions release energy to the surroundings, like a fire giving off heat.
• 🌨️ Endothermic reactions absorb energy from the surroundings, similar to a melting snowman taking in heat.
• 🔎 The prefix 'exo' means external, indicating energy is given out, while 'endo' means internal, indicating energy is taken in.
• 🌡️ Exothermic reactions can be detected by an increase in temperature, often measured with a thermometer.
• 🧪 Examples of exothermic reactions include neutralization reactions, reactions between water and calcium oxide, and respiration.
• 🛑 Most chemical reactions are exothermic, releasing heat as a byproduct.
• ❄️ Freezing and condensation are exothermic processes because they involve forming bonds, which releases energy.
• 🌡️ Endothermic reactions can be detected by a decrease in temperature, also using a thermometer.
• 💧 Examples of endothermic reactions include electrolysis, the reaction between sodium carbonate and ethanoic acid, and photosynthesis.
• 🔋 In endothermic reactions, energy is added to break bonds, such as when melting a solid or boiling a liquid.
• 📉 The energy curve for exothermic reactions shows reactants with higher energy than products, while for endothermic reactions, products have higher energy.

Q & A

What is the primary difference between exothermic and endothermic reactions?

Exothermic reactions give off energy to the surroundings, such as heat, while endothermic reactions take in energy from the surroundings.

How can you detect whether a reaction is exothermic or endothermic?

You can use a thermometer to detect the change in temperature. Exothermic reactions will cause the surroundings to heat up, whereas endothermic reactions will cause the surroundings to get colder.

What is an example of an exothermic reaction mentioned in the script?

One example of an exothermic reaction is the neutralization reaction between acids and alkalis, such as the reaction between hydrochloric acid and sodium hydroxide.

Why are most chemical reactions exothermic?

Most chemical reactions are exothermic because they involve the release of energy, often in the form of heat, which is a common byproduct of chemical changes.

What is the energy level relationship between reactants and products in exothermic reactions?

In exothermic reactions, the energy of the reactants is higher than that of the products, as energy is released to the surroundings.

Can physical processes be exothermic or endothermic? If so, provide examples.

Yes, physical processes can be exothermic or endothermic. Freezing and condensation are exothermic as they release energy when bonds are formed, while melting and boiling are endothermic as they require energy to break bonds.

What is the meaning of 'Exo' and 'Endo' in the context of reactions?

In the context of reactions, 'Exo' means external, indicating that energy is given out, and 'Endo' means internal, indicating that energy is taken in.

What are some examples of endothermic reactions provided in the script?

Examples of endothermic reactions include electrolysis, the reaction between sodium carbonate and ethanoic acid, and photosynthesis.

How does the energy curve for exothermic reactions differ from that of endothermic reactions?

For exothermic reactions, the energy curve shows that the energy of the reactants is higher than that of the products, indicating energy is released. In contrast, for endothermic reactions, the energy of the products is higher than that of the reactants, indicating energy is absorbed.

Why does the melting of a snowman represent an endothermic process?

The melting of a snowman is an endothermic process because energy is required to break the bonds holding the solid structure together, transitioning it from a solid to a liquid state.

What is the relationship between the energy of the surroundings and the type of reaction taking place?

In exothermic reactions, the surroundings get hotter as energy is released, while in endothermic reactions, the surroundings get colder as energy is absorbed.

Outlines

00:00

🔥 Exothermic and Endothermic Reactions Overview

This paragraph introduces the concepts of exothermic and endothermic reactions, explaining the fundamental differences between the two. Exothermic reactions release energy to the surroundings, such as a fire emitting heat, while endothermic reactions absorb energy from the environment, like a melting snowman. The terms 'exo' and 'endo' are derived from 'external' and 'internal,' respectively, indicating the direction of energy transfer. The video promises to delve into these reactions, their energy levels, and how they can be identified using a thermometer.

Keywords

💡Exothermic Reaction

An exothermic reaction is a type of chemical reaction that releases energy, usually in the form of heat, to its surroundings. This concept is central to the video's theme of understanding energy transfer in chemical reactions. For example, the video mentions a fire giving off heat, which is an exothermic process. The energy curve for exothermic reactions is characterized by reactants having higher energy than the products, as seen when hydrochloric acid and sodium hydroxide are mixed, causing the temperature to rise.

💡Endothermic Reaction

An endothermic reaction is one that absorbs energy from its surroundings, typically as heat. This is the opposite of an exothermic reaction and is key to understanding how some chemical processes require energy input. The video illustrates this with the example of a melting snowman, which takes in heat from the environment. Endothermic reactions are less common and are characterized by products having higher energy than reactants, as seen in processes like electrolysis and photosynthesis.

💡Energy Transfer

Energy transfer refers to the movement of energy from one system to another, which is a fundamental concept in both exothermic and endothermic reactions. In the video, energy transfer is discussed in the context of how reactions either give off or absorb energy. This is crucial for understanding the dynamics of chemical reactions and their effects on the environment, such as a bonfire warming up the surroundings or a melting snowman cooling them down.

💡Energy Levels

Energy levels in the context of the video refer to the amount of potential energy that molecules in a chemical reaction possess. This is an important concept for distinguishing between exothermic and endothermic reactions. The video explains that in exothermic reactions, reactants have higher energy levels than products, which is why energy is released. Conversely, endothermic reactions involve products with higher energy levels, indicating an energy input is needed.

💡Thermometer

A thermometer is an instrument used to measure temperature, and in the video, it serves as a practical tool for detecting whether a reaction is exothermic or endothermic. By observing changes in temperature, one can infer the nature of the energy transfer occurring. The video suggests using a thermometer to monitor the temperature change when mixing hydrochloric acid with sodium hydroxide, indicating an exothermic reaction due to the rise in temperature.

💡Neutralization Reaction

A neutralization reaction is a specific type of exothermic reaction where an acid and a base react to form water and a salt. This concept is introduced in the video as an example of an exothermic process. The reaction between hydrochloric acid and sodium hydroxide is highlighted, demonstrating how such reactions release heat, which can be observed through the use of a thermometer.

💡Respiration

Respiration is a biological process that is also an exothermic reaction. In the video, it is mentioned as an example of a natural, everyday exothermic process where energy is released. This process is essential for life, as it involves the conversion of glucose and oxygen into energy, carbon dioxide, and water, with heat as a byproduct.

💡Freezing

Freezing is a physical process that is described in the video as exothermic. It involves the transition of a substance from a liquid to a solid state, which requires the formation of bonds and the release of energy. The video uses freezing as an example to contrast with melting, showing that while freezing releases energy, melting requires energy input.

💡Condensation

Condensation is another physical process that is exothermic, as it involves the transition of a gas to a liquid state. The video explains that, similar to freezing, condensation also releases energy because new bonds are formed between molecules. This concept helps to illustrate the general principle that bond formation in physical processes often results in energy release.

💡Melting

Melting is a physical process that is endothermic, as it requires energy input to break the bonds holding a solid substance together so it can become liquid. The video uses the melting of a snowman as a relatable example to explain how endothermic reactions absorb energy from the surroundings, causing a decrease in temperature.

💡Boiling

Boiling is an endothermic process where a liquid is heated until it reaches its boiling point and turns into a gas. The video mentions boiling as an example of an endothermic reaction that requires energy to break the bonds between molecules, allowing them to escape into the gas phase. This process is used to emphasize the energy requirements of endothermic reactions.

Highlights

Exothermic reactions give off energy to the surroundings, like a fire giving off heat.

Endothermic reactions take in energy from the surroundings, like a melting snowman taking in heat.

Exo means external, so giving out, while Endo means internal, so taking in.

Exothermic reactions transfer energy, usually in the form of heat, causing the surroundings to heat up.

Examples of exothermic reactions include neutralization reactions, reactions between water and calcium oxide, and respiration.

Exothermic reactions can be detected with a thermometer, as they cause an increase in temperature.

Physical processes like freezing and condensation are exothermic because they involve bond formation, which releases energy.

In exothermic reactions, the energy of the reactants is higher than that of the products.

Endothermic reactions are less common and involve the absorption of energy from the surroundings.

Endothermic reactions can be detected by a decrease in temperature, as the surroundings get colder.

Examples of endothermic reactions include electrolysis, reactions between sodium carbonate and ethanoic acid, and photosynthesis.

Physical processes like melting and boiling are endothermic because they require energy to break bonds.

In endothermic reactions, the energy of the products is higher than that of the reactants.

Exothermic reactions start with more energy and end with less, while endothermic reactions start with less energy and end with more.

Freezing and condensation are exothermic processes due to bond formation, while melting and boiling are endothermic due to bond breaking.

Exothermic reactions are more common in nature.

Transcripts

In this video we are going to look at exothermic and endothermic reactions. So what are they [how] are they different?

What about their energy levels in the next couple of minutes you'll know everything you need to get started

An exothermic reaction gives off energy to the [surroundings] like this fire giving off heat

Whereas an endothermic reaction takes in energy from its surroundings like this pool melting snowman taking in the heat

just remember Exo means external so giving out an

Endo means internal so taking in let's start by having a quick look

Because exothermic reactions transfer energy to the surroundings, [and] this energy is usually heat energy

They cause the surroundings to heat up. Just like a bonfire keeping everyone warm

Other examples of exothermic reactions are the neutralization reactions between acids and alkalis?

the reactions between water and calcium oxide and respiration

It is easy to detect exothermic reactions. Just get your thermometer and see if the temperature increases

Watch the hydrochloric acid and sodium hydroxide solution being mixed and see how the fellow meter increases

most chemical reactions are exothermic

Because heat is given our physical processes can also be endothermic or exothermic

When something freezes it goes from liquid to solid

Bonds need to be made for this to happen and to make bonds you need to do some work

Thus energy is given out and freezing is exothermic

Similarly when condensation happens because a gas is going to liquid

Again [bonds] need to be made and so energy is given out so freezing and condensation are both exothermic

Because in exothermic reactions energy is given out [to] the surroundings

This means that energy of the reactants is higher and the energy of [the] products hence the energy curve

For the exothermic reactions will look like this now

[let's] have a look at endothermic reactions. These are less common

Remember that endothermic reactions take in energy from the surroundings

Again as with exothermic reactions the energy being transferred is usually [heat]

So in endothermic reactions the surroundings usually get colder

Again, we can detect endothermic reactions with a thermometer because the temperature would get colder some examples of endothermic reactions are

electrolysis the reaction between sodium Carbonate and ethanoic acid and

photosynthesis

Endothermic reactions can also be seen in physical processes where something melts it goes from a solid to a liquid

For this to happen bonds need to be broken and to break bonds energy to be put in like our melting snowman

Boiling is also endothermic because energy needs to be put in to break the bonds for the liquid to turn to gas

because in endothermic reactions energy is added to the reaction the energy of the products is higher than the energy of the reactants and

So the energy curve looks like this, so there you have exothermic and endothermic reactions

all you need to remember is that exothermic reactions give out energy and

endothermic reactions take in energy

both can be detected with a thermometer in

Exothermic reactions the surroundings get hotter and in endothermic reactions the surroundings get colder

exothermic reactions start with more energy and end with less while endothermic reactions start with less energy and end with more

Freezing and condensation are exothermic because bonds need to be made which gives out energy

Melting and boiling are endothermic because bonds are broken which requires additional energy

think of the [snowman] again and finally

Exothermic reactions are more common