# What is the standard enthalpy of formation for diamond?

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## Why standard enthalpy of formation of diamond is not zero?

Out of the various allotropic forms of an element, only the standard heat of formation of the most stable allotropic form is taken as zero. Since graphite and not diamond is the most stable form of carbon therefore, the enthalpy of formation of diamond is not zero.

## What is the relation between Delta H and Delta U?

Delta H is the change in enthalpy which is equal to change in U +P*change in V and the delta U is the change in internal energy of the system.

## Which elements standard enthalpy of formation is not zero?

All elements in their standard states (oxygen gas, solid carbon in the form of graphite, etc.) have a standard enthalpy of formation of zero, as there is no change involved in their formation.

## What is the enthalpy change accompanying?

The heat change during a chemical reaction is called enthalpy and the enthalpy change accompanying a reaction is called reaction enthalpy or enthalpy of reaction (ΔH).

## Which of the following will have zero standard molar enthalpy of formation?

The species which by definition has zero standard molar enthalpy of formation at 298K is. This is possible only for elements, chlorine is a gas at this temperature, but bromines is a liquid, so it is possible only for chlorine .

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## How do you find the standard molar enthalpy?

This equation essentially states that the standard enthalpy change of formation is equal to the sum of the standard enthalpies of formation of the products minus the sum of the standard enthalpies of formation of the reactants. and the standard enthalpy of formation values: ΔH fo[A] = 433 KJ/mol.

## Why are bond enthalpy Reactus minus?

Re: Enthalpy question

For the reactants, bonds are broken and energy is needed for this to happen (endothermic, positive enthalpy change). For the products, bonds are formed, leading to a more stable state, so energy is released (exothermic) and the changes in bond enthalpies are negative.