Enthalpy and hess’ law, Chemistry

Assignment Help:

 

The enthalpy change (ΔH) in a reaction is equal to the heat input under conditions of constant pressure and temperature. It is not equal to the total energy change, as work may be done by expansion against the external pressure. The corrections are usually small, and enthalpy is used as a measure of the energies involved in chemical reactions. Endothermic reactions (positive ΔH) are ones need a heat input, and exothermic reactions (negative ΔH) give a heat output.

Hess' Law states that ΔH does not rely on the pathway taken between initial and final states, and is a consequence of the First Law of Thermodynamics, which asserts the conservation of total energy. It describes a schematic thermodynamic cycle where the ΔH can be expressed as the sum of the values for individual steps:

 

2056_Untitled.png


Related Discussions:- Enthalpy and hess’ law

Protien, discuss secondary structure of pritien

discuss secondary structure of pritien

The nucleus of an element contains 9 protons. its valency, The nucleus of a...

The nucleus of an element contains 9 protons. Its valency would be : (1) 1        (2) 3        (3) 2        (4) 5 Ans: 1

Sources of aliphatic hydrocarbon, Sources of aliphatic hydrocarbon Mine...

Sources of aliphatic hydrocarbon Mineral or crude oil, petroleum is the dark colour oily liquid along with offensive odour found at several depths in many regions below the sur

Analytical tests for fats and oils, Q. Analytical tests for fats and oils? ...

Q. Analytical tests for fats and oils? The analytical tests used in fats and oils are to: • determine the nature of fat or oil or the blends to see whether it is of the typ

Treshold frequency, How is threshold frequency related of the incident radi...

How is threshold frequency related of the incident radiation

D-block element, Write the periods of periodic table have d-block element

Write the periods of periodic table have d-block element

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd