Why is the enthalpy of formation of oxygen zero?
Why is the enthalpy of formation of oxygen 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. So in this case, ΔHrxn,H2O=ΔHf,H2O . We can only measure changes in enthalpy. Now, the enthalpy change for a formation reaction is called enthalpy of formation.
Does O2 have a heat of formation?
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 kJ mol of O2?
O2(g): 0 kJ/mol. NO(g): 90.25 kJ/mol. NO2(g): 33.18 kJ/mol.
What is the molar enthalpy of oxygen?
Molar Enthalpy of Formation of Various Substances
| Substance | Formula | hfo [kJ/kmol] |
|---|---|---|
| Oxygen | O2(g) | 0 |
| Carbon monoxide | CO(g) | -110,530 |
| Carbon dioxide | CO2(g) | -393,520 |
| Water Vapor | H2O(g) | -241,820 |
Is enthalpy change of formation positive or negative?
In general, any enthalpy of reaction is the measure of the energy remainder after breaking the bonds (positive) and what energy we got back from the formation of the bonds (negative).
What is formation of water?
Formation waters are mixtures of original trapped fluids such as seawater and fluids modified by rock–water interaction (hydration or dehydration reactions or crustal transport). From: Encyclopedia of Physical Science and Technology (Third Edition), 2003.
How do you calculate water resistivity formation?
In 1942, Archie introduced the well-known formula for computing water saturation for clean zones as(1) S W n = a R W ϕ m R t where, SW is the water saturation in the uninvaded zone, n is the saturation exponent (usually taken equal to 2), a is the tortusity factor (usually taken equal to 1), Rw is the formation water …
How does oxygen and hydrogen make water?
When molecular hydrogen (H2) and oxygen (O2) are combined and allowed to react together, energy is released and the molecules of hydrogen and oxygen can combine to form either water or hydrogen peroxide.