Which of these represents a chemical change?
A) two compounds combining to form a mixture
B) a mixture being separated into two elements
C) a compound being separated into two elements
D) an element changing state from solid to liquid
which answer uses the word "compound"?
The correct answer is C) a compound being separated into two elements.
To understand why this is a chemical change, we need to have a basic understanding of chemical reactions and changes. A chemical change refers to a process where the chemical composition of a substance is altered, resulting in the formation of a new substance. In other words, the identities of the atoms or molecules present in the substance are changed.
Option A, "two compounds combining to form a mixture," is a physical change rather than a chemical change. Physical changes involve alterations in the physical properties of a substance, like shape, size, or state, but do not result in a new substance being formed. In this case, the identity of the atoms or molecules remains the same; they are only physically combined.
Option B, "a mixture being separated into two elements," is also a physical change. The separation of a mixture into its individual components does not involve any alteration of the chemical composition of the substances. The individual elements retain their original identities.
Option D, "an element changing state from solid to liquid," is again a physical change. Changing from a solid to a liquid state is simply a phase transition, involving rearrangement of the particles while maintaining their chemical identities.
However, in option C, "a compound being separated into two elements," a chemical change occurs. A compound is made up of atoms of different elements bonded together. When the compound is separated into its constituent elements, the chemical bonds between atoms are broken, and new substances (the individual elements) are formed. This chemical separation results in a change in the composition of the substance.
So, if you encounter a scenario where a compound is being broken down into its constituent elements, you can confidently say that it represents a chemical change.