The amount of heat evolved when 1 kg of a fuel is burnt completely is called its ________.

Explanation

**Step-by-Step Solution:**

1. **Understanding the Question**: The question asks for the term that describes the amount of heat released when 1 kg of fuel is completely burned.

2. **Identifying the Term**: The specific term used in chemistry to describe the heat produced from burning fuel is known as the "calorific value."

3. **Definition of Calorific Value**: Calorific value is defined as the amount of heat energy released when a specified amount of fuel (in this case, 1 kg) is completely combusted.

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