When we say “change”, we’re talking about a chemical reaction. The change from one substance to another occurs in a process called a chemical reaction. This process changes the original substance into something else entirely. Here are some of the main types of chemical reactions: Combination, Separation, and Rearrangement. If you’re wondering about these types of reactions, read on to learn about them. Here’s a quick review.
Physical change
Physical changes occur when molecules react with each other. These changes change matter’s composition and appearance. A chemical reaction occurs when two or more molecules come in contact with one another. The type of reaction depends on the types of molecules and their interactions. Physical changes don’t change the material itself, but the surface of the object changes. Similarly, a chemical reaction can change the texture of something. For example, a piece of wood may become smooth after sandpapering, but the actual material remains the same.
Combination
Combination is a chemical reaction in which two elements combine directly to form a new substance. The reaction is characterized by equations of the form X + Y XY. It can be described by a number of different examples. Here are the common ones:
Separation
Chemical reaction of separation processes involve two immiscible liquid phases, one of which is the solvent, and the other a polar phase. The solvent extracts the solutes from the other phase, which is followed by raffinate cleanup. The process design plays a pivotal role, as does the selection of solvents. As customer demands and technology evolve, new challenges and opportunities arise for chemical industries. In this chapter, we discuss new approaches to separation technologies, and explore opportunities for improving these techniques.
Rearrangement
Rearrangement reactions are important steps in many organic reactions, and they play an important role in functional group transformations and modern synthetic chemistry. This chapter is intended to complement other discussions in this book on rearrangements. It will not cover aromatic rearrangements or allylic rearrangements during substitution, nor will it discuss reductive transposition. To understand these reactions, see the book Organic Reaction Mechanisms: Structure and Function, edited by Knipe and Watts.
Color change
A chemical reaction causes color change in water. The reddish color of blood is caused by a chemical reaction in water. Oxygen from swirling changes indigo carmine from red to green. The reaction also produces an intermediate colored substance called a semiquinone, which changes color from yellow to red. As the concentration and temperature increase, the color changes quickly, and the reaction occurs faster. This chemistry demonstration is great for Halloween or Valentine’s Day!
Precipitate formation
The process of precipitation involves the dissociation and rebonding of dissolved substances into solids and ions. Various special equations are developed to model the process. In general, precipitation reactions occur when the concentration of a substance is higher than its solubility. Also known as the molecular equation, the formula combines the properties of the dissolved materials with their states. The result is a precipitate formed by the chemical reaction.
Speed of reaction
In addition to the changes in size of reagents, chemical reactions may change the aggregate state of these compounds. A chemical reaction also changes the concentration per unit of time. Scientists use catalysts to speed up reactions. The ideal catalyst combines two of the most important properties of a chemical reaction: it should have the right amount of energy to promote the reaction and adhere to the metal surface. This is why it is often called the “Goldilocks” principle of catalysis.
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