Question

Which is the metric standard for measuring energy? Which unit is used for specific heat capacity? If you wanted to compare the abilities of olive oil and peanut oil to gain or lose thermal energy, which unit would you use?

Answer 1

1. Which is the metric standard for measuring energy?

The metric standard for measuring of energy defined by the International System of Units is the joule (J), which is defined as the work done by a force of a newton in a displacement of one meter in the direction of force. So,

1 J = 1 N m = 1 kg·m²/s²

Calorie is also frequently used in scientific and technological applications. Calorie is a unit of thermal energy that is equivalent to the amount of heat needed to raise the temperature of 1 gram of water by 1 degree Celsius.

1 cal = 4,184 J

2. Which unit is used for specific heat capacity?

The specific heat capacity (c) is a physical quantity that is defined as the amount of heat (q) that must be supplied to the mass unit of a thermodynamic substance or system to raise its temperature by one unit. So,

c = q / m ΔT

where m is the mass of the substance and ΔT is the temperature increase.

In this way, as heat is a form of energy, the International System of Units expresses the specific heat in joules per kilogram and per kelvin (J kg⁻¹ K⁻¹). Another common unit, not belonging to the SI, is the calorie per gram and per degree centigrade (cal g⁻¹ ° C⁻¹).

3. If you wanted to compare the abilities of olive oil and peanut oil to gain or lose thermal energy, which unit would you use?

You should use units of specific heat capacity (J kg⁻¹ K⁻¹) since, as mentioned above, this is a physical quantity that measures the amount of heat that must be supplied to an specific mass of a substance or system to raise its temperature.

Heat is a thermal energy, so by using heat capacity units you can compare the ability of olive oil and peanut oil to gain or lose thermal energy by varying its temperature.

Answer 2

The first one: joules
second one: J/g°C
third one: J/g°C