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

Equivalent weight, Equivalent weight of Ca in Ca3(PO4)2 is

Equivalent weight of Ca in Ca3(PO4)2 is

Special topics in analytical chem, Q1. a). Using diagram, explain how fluor...

Q1. a). Using diagram, explain how fluorescence detector optical bench works (5 marks) (b). Explain the applications of mass spectrometric detector (LC/MS) in HPLC (5 mar

Explain propene, Explain propene In propene, the H 3 C-C bond d...

Explain propene In propene, the H 3 C-C bond dipole adds vectorially to the smaller H-C bond dipole; the resultant is smaller than the H 3 C-C bond dipole itself, as th

Effect of heat on metal carbonates, what are some issues that can be discus...

what are some issues that can be discussed in the project?

Silver salt method for acids - chemical methods, Silver salt method for aci...

Silver salt method for acids - Chemical methods It is based upon the fact that silver salt of an organic acid on heating provides residue of metallic silver.

What do you understand by miller indices of a crystal plane, What do you un...

What do you understand by Miller indices of a crystal plane? Miller Indices are a symbolic vector representation for the orientation of an atomic plane in a crystal lattice an

Stereochemical relationship, A monosaccharide A has a molecular weight of 1...

A monosaccharide A has a molecular weight of 150 Da. The two stereoisomers B and C that are both optically inactive form when A reacts with NaBH4.  Show all dissimilar stereoiso

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