What are the main characteristics of a chemical change?

Explanation

To answer the question about the main characteristics of a chemical change, we can break it down into three key points:

### Step-by-Step Solution:

1. **Irreversibility**:
- One of the main characteristics of a chemical change is that it is generally irreversible. Once a chemical change has occurred, the original substances cannot be easily recovered or reverted back to their initial state. For example, when wood burns, it turns into ash and gases, which cannot be transformed back into wood.

2. **Energy Change**:
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