Heat capacity calculator

Calculates the energy consumed for heating a specific substance. See power consumption for heating of air, water, gold, hydrogen, and more. Answer in kJ, kcal, and kWh.
Varmekapasitet illustrert med vannmolekyler
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Heat capacity calculator

Calculating heat capacity

Specific heat capacity is a crucial concept in thermodynamics that pertains to the amount of heat required to raise the temperature of a particular substance per unit of its mass. This article will explain the concept of specific heat capacity, the formula for its calculation, and its practical applications in everyday life.
Heat capacity illustrated with water molecules
Specific heat capacity is the heat capacity per unit mass of a particular substance, such as air or water. There is a specific system of units used to measure these values, called the SI system. In the calculation of specific heat capacity, we use the units Joule (energy), Kelvin (temperature), and Kilogram (weight). The formula is J/(K*kg). J stands for Joule, K stands for Kelvin, and kg stands for Kilogram.

The heat capacity of air is 1.005 kJ/kg and the heat capacity of water is 4.183 kJ/kg.

This means that it takes 1005 Joules to increase the temperature of 1 kilogram of air by 1 degree Celsius, and it takes 4183 Joules to increase the temperature of 1 kilogram of water by 1 degree Celsius.

As we can see, water has a high value for heat capacity, but what does that mean in practical terms?

Some of us have taken a bath on a summer evening and felt that the water, which was heated by the warm sun earlier in the day, is warmer than the air after the sun has gone down. This is specific heat capacity in action, where we can feel on our body that the air has easily changed its temperature, and the water has not changed its temperature as quickly.

Water has good properties for storing heat. Water is also an excellent conductor of heat and is widely used for heating and cooling of homes and commercial buildings.

About the calculator

To calculate how much energy is required to increase the temperature of a substance, we need to know the weight of the substance in kilograms.

We also need to know the specific heat capacity of the substance.

Specific heat capacity is a measure of how much energy is required to raise the temperature of a substance. Heat capacity is defined as the ratio of heat added to a substance to the resulting temperature increase. See the list and paragraph below.

The temperature increase we want to achieve must also be defined in the calculation as a starting temperature and ending temperature. This difference is called "delta temperature" and is represented by the symbol ∆.

Temperature can be expressed in degrees in the kelvin or celsius scale, and we choose celsius because most people are familiar with this temperature scale from thermometers and weather reports.

The formula for calculation is Q = m * c * ∆T

1 liter of water weighs 1 kilogram at 4⁰ degrees. For example, if 10 liters of water are to be heated from 20⁰ to 30⁰ degrees celsius, the calculation is as follows: 10 kilograms (m) * 4.183 kJ/kg (c) * 10⁰ degrees celsius (30⁰-20⁰) (∆T) = 418.6 kJ (Q).

Air also has a weight, even though we might not think about it. At sea level, a cubic meter of dry air weighs about 1.25 kilograms. This is called atmospheric air. The air higher up in the atmosphere weighs a lot, but since the air pressure is distributed evenly around us, we don't notice it.

However, we can feel air resistance in the air when we cycle, or hold our hand out of a car window while moving. The faster we move, the higher the air resistance becomes, and the more we notice that the air has a weight that is moved when we move.

As an example, let's consider a room that is 5 meters long, 2.5 meters wide, and 2.5 meters high. The formula for calculating the volume is length * width * height, and in this example it is 31.25 cubic meters. To find the weight of the air in the room, we must multiply the number of cubic meters by the specific weight of air, and in this case it is 1.25 kilograms * 31.25 cubic meters = 39.06 kilogram.

By entering the number of kilogram, the desired temperature increase, and the selected substance, our calculator will calculate how much energy is needed to heat up the substance. You will get the answer in kJ and kcal, as well as kWh to get an even better perspective on the consumed power and cost. Just enter the numbers and let the calculator do the work quickly and efficiently!

Note: The specific heat capacity in our list is given at constant pressure and at a temperature of 20 degrees Celsius.

Heat capacity for substances in the calculator

Substance Heat capacity
Air 1.005 kJ/kg
Aluminum 0.896 kJ/kg
Copper 0.385 kJ/kg
Glycerol 2.390 kJ/kg
Gold 0.129 kJ/kg
Graphite 0.708 kJ/kg
Helium 5.230 kJ/kg
Hydrogen 14.32 kJ/kg
Iron 0.452 kJ/kg
Lead 0.129 kJ/kg
Lithium 3.390 kJ/kg
Silver 0.234 kJ/kg
Sodium 1.210 kJ/kg
Uranium 0.117 kJ/kg
Water 4.183 kJ/kg
Source: SNL.NO

FAQ

What is a Joule?
Joule is a unit of measurement for energy, indicated by the symbol "J". A joule is the amount of energy required to move something against a force of 1 newton over a distance of 1 meter. A joule is also equal to the energy released by 1 watt of power in 1 second. This is called a "watt-second". Increasing the values to kilowatts per hour (kWt) will bring us to the unit of measurement that we see on the electricity bill.
What is a calorie?
A calorie is a unit of measurement for energy, indicated by the symbol "cal". A calorie is the amount of energy required to raise the temperature of 1 gram of water by 1 degree Celsius. Calories are often given for food as kilocalories, and we use kilocalories "kcal" in the calculation to give perspective on the consumed energy.
What is a Kelvin?
Kelvin is the basic unit of measurement for temperature. Kelvin is included in the international system of units for measuring physical quantities. A kelvin is defined using universal constants and is not based on physical objects. A kelvin is defined as a value and is not defined as a degree like Celsius or Fahrenheit are defined by the number of degrees. The zero point on the kelvin scale is the absolute zero point, which means the lowest temperature that is possible to achieve in physics is 0 kelvin. In comparison, the absolute zero point can be expressed as -273.15 degrees Celsius, and -459.67 degrees Fahrenheit.
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