# How to Calculate and Solve for Internal Latent Heat | Enthalpy

**Last Updated on May 23, 2024**

The internal latent heat is illustrated by the image below. To calculate the internal latent heat, four essential parameters are needed and these parameters are **Enthalpy of Vapourization (h _{fg}), Specific Volume of Gas (v_{g}), Pressure (P)** and

**J.**

**The formula for calculating internal latent heat:**

L = h_{fg} – ^{Pvg} / _{J}

Where:

L = Internal Latent Heat

h_{fg} = Enthalpy of Vapourization

v_{g} = Specific Volume of Gas

P = Pressure

Given an example;

Find the internal latent heat when the enthalpy of vapourization is 22, the enthalpy of vapourization is 12, the specific volume of gas is 10 and J is 1.

This implies that;

h_{fg} = Enthalpy of Vapourization = 22

v_{g} = Specific Volume of Gas = 12

P = Pressure = 10

L = h_{fg} – ^{Pvg} / _{J}

L = 22 – ^{10 x 12} / _{1}

That is, L = 22 – ^{120} / _{1}

L = 22 – 120

L = -98

Therefore, the **internal latent heat **is **-98kg.**

**Calculating the Enthalpy of Vapourization when the Internal Latent Heat, the Specific Volume of Gas and the Pressure are Given**

h_{fg} = L + ^{Pvg} / _{J}

Where:

h_{fg} = Enthalpy of Vapourization

L = Internal Latent Heat

v_{g} = Specific Volume of Gas

P = Pressure

Let’s solve an example;

Find the enthalpy of vapourization when the internal latent heat is 30, the specific volume of gas is 10 and the pressure is 5.

This implies that;

L = Internal Latent Heat = 30

v_{g} = Specific Volume of Gas = 10

P = Pressure = 5

h_{fg} = L + ^{Pvg} / _{J}

h_{fg} = 30 + ^{(10)(5)} / _{1}

Then, h_{fg} = 30 + ^{50} / _{1}

h_{fg} = 30 + 50

h_{fg} = 80

Therefore, the **enthalpy of vapourization **is **80J/Kg.**

Read more: How to Calculate and Solve for Work of Evapouration | Enthalpy

**Calculating the Pressure when the Internal Latent Heat, the Enthalpy of Vapourization and the Specific Volume of Gas are Given**

P = ^{hfg – L} / _{vg} x J

Where:

P = Pressure

L = Internal Latent Heat

h_{fg} = Enthalpy of Vapourization

v_{g} = Specific Volume of Gas

Let’s solve an example;

Find the pressure when the internal latent heat is 24, the enthalpy of vapourization is 35 and the specific volume of gas is 10.

This implies that;

L = Internal Latent Heat = 24

h_{fg} = Enthalpy of Vapourization = 35

v_{g} = Specific Volume of Gas = 10

P = ^{hfg – L} / _{vg} x J

P = ^{35 – 24} / _{10} x 1

So, P = 1.1 x 1

P = 1.1

Therefore, the **pressure **is **1.1J/Kg.**

Read more: How to Calculate and Solve for Enthalpy at Constant Pressure Heating or Cooling | Enthalpy

**Calculating the Specific Volume of Gas when the Internal Latent Heat, the Enthalpy of Vapourization and the Pressure are Given**

v_{g} = ^{hfg – L} / _{P} x J

Where:

v_{g} = Specific Volume of Gas

L = Internal Latent Heat

h_{fg} = Enthalpy of Vapourization

P = Pressure

Let’s solve an example;

Find the specific volume of gas when the internal latent heat is 20, the enthalpy of vapourization is 40 and the pressure is 2.

This implies that;

L = Internal Latent Heat = 20

h_{fg} = Enthalpy of Vapourization = 40

P = Pressure = 2

v_{g} = ^{hfg – L} / _{P} x J

v_{g} = ^{40 – 20} / _{2} x 1

So, v_{g} = ^{20} / _{2} x 1

v_{g} = 10 x 1

v_{g} = 10

Therefore, the **specific volume of gas **is **10J/Kg.**

**How to Calculate Internal Latent Heat Using Nickzom Calculator**

Nickzom Calculator – **The Calculator Encyclopedia** is capable of calculating the internal latent heat.

To get the answer and workings of the internal latent heat using the **Nickzom Calculator – The Calculator Encyclopedia. **First, you need to obtain the app.

You can get this app via any of these means:

**Web** – https://www.nickzom.org/calculator-plus

To get access to the **professional **version via web, you need to **register** and **subscribe **to have utter access to all functionalities.

You can also try the **demo **version via https://www.nickzom.org/calculator

**Android (Paid)** – https://play.google.com/store/apps/details?id=org.nickzom.nickzomcalculator

**Android (Free)** – https://play.google.com/store/apps/details?id=com.nickzom.nickzomcalculator

**Apple (Paid)** – https://itunes.apple.com/us/app/nickzom-calculator/id1331162702?mt=8

Once, you have obtained the calculator encyclopedia app, proceed to the **Calculator Map, **then click on **Materials and Metallurgical **under **Engineering****.**

Now, Click on **Chemical Reaction Thermodynamics**** **under **Materials and Metallurgical**

Then, Click on **Enthalpy** under **Chemical Reaction Thermodynamics
**

Now, Click on **Internal Latent Heat **under **Enthalpy**

The screenshot below displays the page or activity to enter your values, to get the answer for the internal latent heat according to the respective parameter which is the **Enthalpy of Vapourization (h _{fg}), Specific Volume of Gas (v_{g}), Pressure (P)** and

**J.**

Now, enter the values appropriately and accordingly for the parameters as required by the **Enthalpy of Vapourization (h _{fg})** is

**22**,

**Specific Volume of Gas (v**is

_{g})**12**,

**Pressure (P)**is

**10**and

**J**is

**1**.

Finally, Click on Calculate

As you can see from the screenshot above, **Nickzom Calculator**– The Calculator Encyclopedia solves for the internal latent heat and presents the formula, workings and steps too.