What do these chem symbols mean? --enthalpy related?

Question

I don't know how to type them on the computer but....

(delta)H(superscript with a degree symbol)(subscript with an f)?

(delta)H(superscript with a degree symbol)(no subscript)?

Answer 1

The first one is change in heat of formation at STP.
The second one is the change in enthalpy at STP.
STP means standard temperature and pressure which is 298 K and 1 atm.

Answer 2

Enthalpy Symbol

Answer 3

It's the standard enthalpy of formation. Meaning, the enthalpy of breaking the bonds (positive enthalpy) or forming the bonds (negative enthalpy) at standard conditions.

Answer 4

I can only guess at part of this. Delta refers to a changed value. degree symbol subscript f may refer to degrees Fahrenheit. I've no clue what the H is for. Heat maybe?

Answer 5

With the f = heat of formation

With out it = change in entalpy (or heat of reaction)

The degree sign = at standard conditions

Standard conditions = 25 degrees C (298 degrees K) and 1 atmosphere of pressure

Answer 6

H is the symbol for enthalpy.
delHf is the heat of formation
delHo is the enthalpy at a standard state.

Answer 7

standard enthalpy of formation

standard change in enthalpy

Answer 8

change in enthalpy ( either formation or maybe fusion)
-some textbooks use deltaHf for heat of fusion

http://en.wikipedia.org/wiki/Enthalpy_of_formation
http://en.wikipedia.org/wiki/Heat_of_fusion

and

change in enthalpy (at standard conditions ie 25 C, 1 atm pressure, 1.0 molar concetration ect.)

Answer 9

1)standard enthalpy
2)molar enthalpy

( i think)

Answer 10

try the link under pal ,,,, tried to look for it myself ,,,, its something simalar to dragon,,,, better of success ,,, p.s. try making constructive you recognize what your getting nxt time ma guy !!