Final answer:
The term for the heat required to raise the temperature of a 1-kilogram substance by 1°C is the 'specific heat' capacity, a core concept in thermodynamics.
Step-by-step explanation:
The amount of heat needed to increase the temperature of a 1-kilogram substance by 1°C is known as the specific heat capacity. Specifically, specific heat refers to the quantity of heat required to raise the temperature of 1 gram of a substance by 1 degree Celsius (or 1 kelvin). This is a fundamental concept in thermodynamics and is critical for understanding how different substances respond to heat.