Can the enthalpy of formation be zero?

The standard enthalpy of formation of any element in its most stable form is zero by definition. (which is pronounced “delta H eff naught”). The standard enthalpy of formation of any element in its standard state is zero by definition. Therefore, O 2(g), H 2(g), and graphite have ΔHof values of zero.

Which substances have zero value of standard enthalpy of formation?

The standard enthalpy of formation of a pure element is in its reference form its standard enthalpy formation is zero. Carbon naturally exists as graphite and diamond. The enthalpy difference between graphite and diamond is too large for both to have a standard enthalpy of formation of zero.

Is it true that the standard enthalpy of formation is 0 for any pure element Why or why not?

The standard enthalpy of formation for an element in its standard state is ZERO!!!! Elements in their standard state are not formed, they just are. So, ΔH f o for C (s, graphite) is zero, but the ΔH f o for C (s, diamond) is 2 kJ/mol. That is because graphite is the standard state for carbon, not diamond.

Which of the following has a standard enthalpy of formation which is not zero?

The correct answer is methane, S8(monoclinic), and H(g). These three compounds have a non-zero value of enthalpy of formation.

Why the standard enthalpy of formation is zero?

The enthalpy of formation for an element in its elemental state will always be 0 because it takes no energy to form a naturally-occurring compound. When a substance is formed from the most stable form of its elements, a change in enthalpy takes place.

What has a standard enthalpy of 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.

Which substance has a standard enthalpy of formation equal to zero at 25 C?

Graphite
Graphite and diamond are both forms of elemental carbon, but because graphite is more stable at 1 atm pressure and 25°C, the standard state of carbon is graphite (Figure 7.8. 1). Therefore, O2(g), H2(g), and graphite have ΔHof values of zero.

Which of the following has a standard enthalpy of formation of zero at 25 C?

Cl2(g) have standard enthalpy of formation value is zero at 25°C .

Which of the following has a heat of formation equaling zero quizlet?

Which of the following has an heat of formation equaling zero? Explanation: Elements that are in their natural state have an enthalpy of formation that is equal to zero. F₂ is the only element on the list that is in its natural state.

What is the equation that represents the standard enthalpy of formation of liquid ethanol?

Problem #17: (a) The standard enthalpy of formation of ethanol, C2H5OH(ℓ), is −278 kJ mol¯1. Write a thermochemical equation which represents the standard enthalpy of formation of ethanol….Solution:

C2H2(g) + 5⁄2O2(g) —> 2CO2(g) + H2O(ℓ)	ΔH comb o = −1301.1 kJ
H2(g) + 1⁄2O2(g) —> H2O(ℓ)	ΔH comb o = −285.8 kJ