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

Elements easily forms cation, From the following which group of elements ea...

From the following which group of elements easily forms cation: (1) F, CL, Br                         (2) Li,  Na, K         (3)  O, S, Se,                       (4)

zinc oxide through reduction with co, why zinc extracted from zinc oxide t...

why zinc extracted from zinc oxide through reduction with co? Ans) Reducing agent should have more negative ΔG value. In case of zinc oxide ,Zn has more negative ΔG value then CO

Filter, Filter A plant pot with a plug of cotton wool in the bottom and...

Filter A plant pot with a plug of cotton wool in the bottom and a layer of sand little inches deep makes a satisfactory filter for more purposes

Transition metals, what is the advantages of preparing interstitial compoun...

what is the advantages of preparing interstitial compounds

Determine the wavelength of light wave, Q. Determine the wavelength of ligh...

Q. Determine the wavelength of light wave? Ans. The frequency of an infrared wave is 2.07 x 10 14 Hz. What is the wavelength?  c = λv Since we know the speed of light we

Organic compounds , What Is The B...

What Is The Benefits Of Alkenes?

Uncertainty in the position of a moving bullet of mass, The uncertainty in ...

The uncertainty in the position of a moving bullet of mass 10 gm is 10 -5 m  . Calculate the uncertainty in its velocity: (1) 5.2 x 10 -28 / sec                         (

Number of unpaired electrons in nitrogen, The number of unpaired electrons ...

The number of unpaired electrons in nitrogen is: (1) 1        (2) 3        (3) 2        (4) None of these Ans: 3

Halides, why pcl3 and s2cl2 are less polar then sicl4

why pcl3 and s2cl2 are less polar then sicl4

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