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

Draw the structures of white phosphorus and red phosphorus, Draw the struct...

Draw the structures of white phosphorus and red phosphorus. Which one of these two types of phosphorus is more reactive and why?

Atomic structure and periodicity, what are the pattern og ionic radii and a...

what are the pattern og ionic radii and atomic radii for p block element?

Homework, silicon carbide is prepared using the chemical reaction SiO2+3C p...

silicon carbide is prepared using the chemical reaction SiO2+3C producing SiC+2CO so how many grams of SiC can be produced from 15 grams of C

Electronegative atom on the strength of ionic bond, What is the effect of m...

What is the effect of more electronegative atom on the strength of ionic bond: (1) Decreases (2) Increase (3) Decreases slowly (4) Remains the same Ans:  Increase

Freezing and Boiling points, Calculate the molarmass of a nonelectrolyte th...

Calculate the molarmass of a nonelectrolyte that lowers the freezing point of 25.00g of water to -3.9 degrees C when 4.27 g of the substance is dissolved in the water.

Physical properties of trihydric alcohols, Physical properties of Trihydric...

Physical properties of Trihydric alcohols (a) Trihydric alcohol is an odourless, viscous, colourless and hygroscopic liquid. (b) Trihydric alcohol has high boiling point tha

Origin and abundance of the elements, ORIGIN AND ABUNDANCE OF THE ELEMENTS ...

ORIGIN AND ABUNDANCE OF THE ELEMENTS The synthesis of elements needs nuclear reactions, of which the most important type is the fusion of two light nuclei to prepare one of

Uses of formic acid - carboxylic acids, Uses of Formic acid - Carboxylic ac...

Uses of Formic acid - Carboxylic acids (a) Formic acid is used in the laboratory for preparation of carbon monoxide. (b) Formic acid is used in the preservation of fruits.

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