Question Video: Identifying an Image That Represents a Thermal Decomposition Reaction | Nagwa Question Video: Identifying an Image That Represents a Thermal Decomposition Reaction | Nagwa

# Question Video: Identifying an Image That Represents a Thermal Decomposition Reaction Science • Third Year of Preparatory School

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Which of the following images best represents a thermal decomposition reaction? [A] Image A [B] Image B [C] Image C [D] Image D [E] Image E

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### Video Transcript

Which of the following images best represents a thermal decomposition reaction?

In this question, we are being asked to determine which of the images below shows a thermal decomposition reaction.

A decomposition reaction is a type of chemical reaction in which a compound is broken down into simpler substances. The simpler substances that are produced in the reaction may be compounds or elements. Sometimes, it’s necessary to heat a substance to cause a decomposition reaction to occur. We refer to this type of reaction as a thermal decomposition reaction. Therefore, we can define a thermal decomposition reaction as the breaking down of a substance when heated to form two or more other substances.

If we look at the images we can see that circles of different colors have been used to represent different atoms or ions in various compounds. Each image also contains an arrow with a triangle symbol above it. This symbol, known as Δ, indicates that the reactants are being heated.

We know that when a thermal decomposition reaction occurs, two or more different products will be formed. We can see that reactions (A) and (B) only produce a single compound. Because these reactions only form one product, they are not thermal decomposition reactions.

Our definition of a thermal decomposition reaction also tells us that the reaction must have only one reactant. In other words, the image must have a single chemical compound as a reactant. In reactions (C) and (D), a plus sign is used to indicate that there are two different reactants. Therefore, these two reactions are not thermal decomposition reactions.

You might also have noticed that in these two reactions, some of the colored circles have changed positions. So, these reactions are likely to be substitution reactions.

As for reaction (E), we see that one chemical compound reacts to form two different products. This fits well with our definition of a thermal decomposition reaction. Therefore, the image that best represents a thermal decomposition reaction is image (E).

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