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

Ion, How ion works?

How ion works?

Phenol, what is trihydric phenol and hownit is works

what is trihydric phenol and hownit is works

Calculate the feed rate of water, Liquid-liquid extraction is used to separ...

Liquid-liquid extraction is used to separate acetone and MIBK. A mixture of acetone and MIBK is fed to a mixing tank at a rate of 100 kg/min. Pure water is also fed to the tank and

Define structure of cis-1-3-dimethylcyclohexane, The two chair conformation...

The two chair conformations of cis-1,3-dimethylcyclohexane

To prepare crystals of pure phthalic acid from impure sample, what will be ...

what will be theory of phthalic acid of crystallization?

Sulphur in vapour state exhibits paramagnetic behaviour, Define the followi...

Define the following observations: (i) Most of the known noble gas compounds are those of xenon. (ii) CIF3 exists but FCI 3 does not. (iii) Between the hydrides of elemen

Draw a temperature-composition phase diagram, Q. Use the following informat...

Q. Use the following information to draw a temperature-composition phase diagram for the binary system of H 2 O (A) and Na 2 SO 4 (B) at p = 1 bar, confining t to the range 20 to

General , Match the compounds below with the type of bonding each predomina...

Match the compounds below with the type of bonding each predominately exhibit. Question 3 options: NaCO3 NaBr SOCl2 CH4 1. ionic bonding 2. covalent bonding

Bohr orbits in an atom of hydrogen, In Bohr series of lines of hydrogen spe...

In Bohr series of lines of hydrogen spectrum, the third line from the red end corresponds to which one of the following inter-orbit jumps of the electron for Bohr orbits in an atom

Bohr model of an atom could not account for, Bohr model of an atom could no...

Bohr model of an atom could not account for : (1) Emission spectrum   (2) Absorption spectrum   (3) Line spectrum of hydrogen  (4)Fine spectrum Ans:  Fine spectrum

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