Define heat capacity of a substance.

Explanation

**Step-by-Step Solution:**

1. **Understanding Heat Capacity**: Heat capacity is a physical property of a substance that indicates how much heat energy is needed to change its temperature.

2. **Definition**: The heat capacity of a substance is defined as the amount of heat energy required to raise the temperature of that substance by 1 Kelvin (or 1 degree Celsius).

3. **Formula**: The heat capacity (C) can be mathematically expressed as:
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