Fill in the following blanks with suitable words :
Changes in which new substances are formed are called _____ changes.

Explanation

**Step-by-Step Solution:**

1. **Understanding the Question:** The question asks for a term that describes changes where new substances are formed.

2. **Identifying the Type of Change:** There are two main types of changes in chemistry: physical changes and chemical changes. Physical changes do not result in the formation of new substances, while chemical changes do.

3. **Defining Chemical Changes:** Chemical changes are processes that involve the transformation of substances into new substances with different properties. This often involves a chemical reaction.

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