# Understanding Specific Heat Units (hg-C)

• scumbum22
In summary, the specific heat of air is typically expressed as 1 kJ/kg.K or kJ/kg.C, depending on temperature. The unit of measurement is energy per unit of mass per unit of temperature. The given value of 1.05 kJ/hg-C is most likely a typo, as the correct unit is kJ/kg-C.
scumbum22
Hopefully this is a really simple question to answer. A problem I have uses the following information:

The specific heat of air = 1.05 kJ/hg-C.

Does anyone know what the hg-C stands for? I know specific heat is usually expressed in terms of J/C, so this is confusing me.

The units of specific heat are energy per unit of mass per unit of temperature. Thus it should read kJ/(kg C). I think you misread the unit and ended up with hg instead of kg.

Nope, I double checked and the units are definitely kJ/(hg-C). Any ideas as to what the hg may be? Is it some reference to mercury?

It doesn't refer to mercury. Let's say it's a typing mistake. I stand by my previous post

The specific heat of air is of the order of 1 kJ/kg.K (or kJ/kg.C). The exact value depends on temperature. So it is a typo, no doubt.
The units J/C (asuming C stands for Celsius degree) are for heat capacity and not for specific heat.

## 1. What is specific heat and why is it important?

Specific heat is the amount of heat required to raise the temperature of one gram of a substance by one degree Celsius. It is an important property because it helps us understand how materials respond to changes in temperature and how much energy is needed to heat or cool them.

## 2. How is specific heat measured?

Specific heat is typically measured in units of joules per gram per degree Celsius (J/g°C). This is done by conducting experiments where the substance is heated or cooled and the resulting change in temperature is measured.

## 3. What factors affect the specific heat of a substance?

The specific heat of a substance is affected by its molecular structure, density, and phase. Substances with stronger intermolecular forces tend to have higher specific heat values, as more energy is needed to disrupt these forces and raise the temperature. Additionally, substances in a solid phase usually have lower specific heat values compared to their liquid or gas phases.

## 4. How does specific heat relate to thermal conductivity?

Specific heat and thermal conductivity are both properties that describe how materials respond to changes in temperature. However, specific heat measures the amount of energy needed to raise the temperature of a substance, while thermal conductivity measures how quickly heat transfers through a substance.

## 5. Can specific heat be changed?

The specific heat of a substance is considered an intrinsic property, meaning it remains constant regardless of the amount or state of the substance. However, the specific heat of a substance may appear to change if the substance is undergoing a physical or chemical change, such as melting or reacting with another substance.

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