Explain what is meant by Enthalpy

In nature, when 2 elements react, energy is taken in to break bonds and energy is given out to form new bonds. The net change in heat energy during a reaction at constant pressure is called the enthalpy change. Enthalpy is denoted by 'delta' H, whereby the symbol delta denotes the difference in energy taken to break bonds and energy taken to make bonds.When system, gives out heat energy to the surroundings, enthalpy is lost by the system. So delta H is negative (exothermic)When system, gives out heat energy to the surroundings, enthalpy is gained by the system. So delta H is positive (endothermic).

Answered by Avishek P. Chemistry tutor

1626 Views

See similar Chemistry A Level tutors

Related Chemistry A Level answers

All answers ▸

What would be the pH of a reaction between potassium oxide and water?


If we burn 3 moles of carbon in air (as per the equation), what mass (in grams) of carbon dioxide will be produced? What volume will this gas occupy at standard temperature and pressure?


Using your knowledge of periodicity and atomic structure, why does the first ionisation energy decrease moving down a group yet increase moving along a period in the periodic table?


You have 3.51g of hydrated zinc sulphate. You heat up the zinc sulphate until all the water has evaporated from it. The weight after heating is 1.97g. Find how many H2O molecules per zinc sulphate molecule there are in the hydrated form of it.


We're here to help

contact us iconContact usWhatsapp logoMessage us on Whatsapptelephone icon+44 (0) 203 773 6020
Facebook logoInstagram logoLinkedIn logo

© MyTutorWeb Ltd 2013–2025

Terms & Conditions|Privacy Policy
Cookie Preferences