What is Latent Heat?

Also explain the Latent Heat of Fusion and Vaporisation!!!!!!!!!!!!!!


5 years ago


Answers : (1)

Latent Heat

When a substance changes phase, that is it goes from either a solid to a liquid or liquid to gas, the energy, it requires energy to do so. The potential energy stored in the interatomics forces between molecules needs to be overcome by the kinetic energy the motion of the particles before the substance can change phase.

If we measure the temperature of the substance which is initially solid as we heat it we produce a graph like Figure(below).

Temperature change with time. Phase changes are indicated by flat regions where heat energy used to overcome attractive forces between molecules

Starting a point A, the substance is in its solid phase, heating it brings the temperature up to its melting point but the material is still a solid at point B. As it is heated further, the energy from the heat source goes into breaking the bonds holding the atoms in place. This takes place from B to C. At point C all of the solid phase has been transformed into the liquid phase. Once again, as energy is added the energy goes into the kinetic energy of the particles raising the temperature, (C to D). At point D the temperature has reached its boiling point but it is still in the liquid phase. From points D to E thermal energy is overcoming the bonds and the particles have enough kinetic energy to escape from the liquid. The substance is entering the gas phase. Beyond E, further heating under pressure can raise the temperature still further is how a pressure cooker works.

Latent Heat of Fusion and Vaporisation

The energy required to change the phase of a substance is known as a latent heat. The word latent means hidden. When the phase change is from solid to liquid we must use the latent heat of fusion, and when the phase change is from liquid to a gas, we must use the latent heat of vaporisation.

The energy require is Q= m L, where m is the mass of the substance and L is the specific latent heat of fusion or vaporisation which measures the heat energy to change 1 kg of a solid into a liquid.

Table show the
Latent Heat !!!!


5 years ago

Post Your Answer

More Questions On Physical Chemistry

Ask Experts

Have any Question? Ask Experts
Post Question
Answer ‘n’ Earn
Attractive Gift
To Win!!!
Click Here for details
I just want a book which makes me able to crack iit jee main and advance in chemistry …. please help me quickly ,.. which book i shoul buy …???
best books for chemistry(jee main and advance) physical- p bahadur and optandon inorganic-jdlee and optandon organic-morrison boyd and arihant publication
Sunil Kumar FP 12 days ago
Discuss the magnetic behaviour of [Fe(CN)6 ] 3– and [FeF6 ] 3–
Fe prefers to exist as Fe3+and is known to have acoordination numberof six. Since the configuration of Fe3+has five d electrons, we would expect to see five unpaired spins in complexes with...
Sunil Kumar FP 6 days ago
In Chemical Bonding , One Type Formation Of Covalent Bond Occurs By Overlapping Of Atomic Orbitals {Sigma} (s-s , s-p ,p-p ) ,Taking Z-Axis As Reference Axis , The Order Of Stability Is :[...
her HF hs the highest bond dissociation energy because of two factors (1)electronegativity difference (2)hydrogen bonding next consider the size factor sizo of H2<F2 molecule hence larger...
Sunil Kumar FP 10 days ago
Thank You For Your Answer Sir , But According To Your ?Statement And Applies Chemistry : “What Will Be The Answer Of The Question : Arrange The Following In Decreasing Order Of Stability ::...
Arpit 10 days ago
IUPAC means International Union of Pure and Applied Chemistry and it is established by UNO and the main aim of this is to develop chemistry and use chemistry for good things in the world.
kumar 4 months ago
International union of pure and applied chemistry..
purva 4 months ago
International Union of Pure and Applied Chemistry
kumar 4 months ago
The dipole moment of hydrogen chloride is 1.03 D. Its percent ionic character is about 17%. Its bond distance in pm is about
Here, we are given the percent ionic character = 17% =0.17, so if r is the bond distance, The dipole moment of HCL is (0.17e)r = (0.17 x 1.6 x 10 –19 C) r = (1.03 x 3.33 x 10 –30 C m) r =...
Vasantha Kumari 3 months ago
h+ and cl- bear a unit charge of 4.8*10^-10 theoritical value of u=4.8*10^-10 *d wher d is the bond distance percentage of ionic character=exp/theoritical*100=17 bond distance=1.27A thanks...
Sunil Kumar FP 3 months ago
Normal 0 false false false MicrosoftInternetExplorer4 Given :- Observed dipole moment = 1.03D % ionic character = 17% Now we know that, mu = e * d = 1.6 * 10 -19 * d/3.335 * 10 -30 mu = 0.48...
Aarti Gupta 2 months ago
what is the differece between ionization potential 1 , ionization potential 2 and ionization potential 3 ??
Ionization potential 1 is the energy reqired to remove the last electron from outer most orbit and IP 2 is energy required to remove the 2 nd elcetron from outer most orbit and IP 3 is...
Sai Pawan 17 days ago
View all Questions »