Math & Science ⇒ Representation of Enthalpy and Heat of Formation

[ghostanime2001]

What is a good way to type enthalpy symbols and heats of formation symbols?

[localghost]

Please elaborate "good way" in this context and give an example. Not everybody knows what the enthalpy and heat formation is and how they are depicted [1]. So it could be helpful if you visualize your ideas.

[1] Standard enthalpy of formation — Wikipedia, the free encyclopedia


Thorsten

[ghostanime2001]

Right now I made this:

Code: Select all

\mathrm{\Enthalpy[exponent=\circ,subscript=right,unit=kJ](f){-92.5}}

but could this somehow be made a little better ? perhaps the little circle and the "f" be pushed apart more or more space around the H and the two little symbols? RIght now, when I view it in pDF it's a little too cramped

In this document I used it like this:

Code: Select all

\documentclass[fleqn]{article} 
\usepackage{amsfonts}
\usepackage{amsmath}
\usepackage{amssymb}
\usepackage{amstext}
\usepackage{amsthm}
\usepackage{booktabs}
\usepackage{calc}
\usepackage[makeroom]{cancel}
\usepackage{chemfig}
\usepackage{chemmacros}
\usepackage[shortlabels,inline]{enumitem}
\usepackage{fix-cm}
\usepackage[T1]{fontenc}
\usepackage{fouridx}
\usepackage{fullpage} 
\usepackage[margin=1in]{geometry} 
\usepackage{graphicx}
\usepackage[utf8]{inputenc}
\usepackage{mathtools}
\usepackage[version=3]{mhchem}
\usepackage{microtype}
\usepackage{multienum}
\usepackage{multirow}
\usepackage{pifont}
\usepackage{pstricks}
\usepackage{siunitx}
\usepackage{textcomp}
\usepackage{type1cm}
\usepackage{ulem}
\usepackage{wasysym}
\usepackage{xfrac}
\usepackage{xspace}
\setlength{\parindent}{0in}
\setlength{\parskip}{0in}
\setlength{\mathindent}{0in}
\allowdisplaybreaks
\pagestyle{empty}
\DisableLigatures{encoding = *, family = *}
\newcommand{\since}{\raisebox{0.56pt}{\rotatebox[origin=c]{180}{$\Large\wasytherefore$}}}
\newcommand{\thus}{\Large{\wasytherefore}}
\newlist{longenum}{enumerate}{6}
\setlist[longenum,1]{label=\arabic*.}
\setlist[longenum,2]{label=\alph*)}
\setlist[longenum,3]{label=\alph*)}
\setlist[longenum,4]{label=(\roman*)}
\setlist[longenum,5]{label=(\alph*)}
\setlist[longenum,6]{label=\roman*)}
\renewcommand*\printatom[1]{\ensuremath{\mathsf{#1}}}
\begin{document}
\hfill Reaction Heats\hfill\llap{Tues, Oct 28, 2008} \par\medskip
\begin{longenum}[nosep,leftmargin=0in]
\item
$\begin{array}[t]{@{}ll@{}}
\ce{N2{\gas} + 3H2{\gas} -> 2NH3{\gas}} &\quad \mathrm{\Enthalpy[exponent=\circ,subscript=right,unit=kJ](f){-92.5}} \\ \addlinespace[\smallskipamount]
\ce{1/2N2{\gas} + 3/2H2{\gas} -> NH3{\gas}} &\quad \mathrm{\Enthalpy[exponent=\circ,subscript=right,unit=kJ](f){-92.5}}
\end{array}$
\end{longenum}
\end{document}

[cgnieder]

Internally chemmacros pretty much makes this when you use \Enthalpy:

Code: Select all

\documentclass{article}
\usepackage{chemmacros}
\begin{document}
\Enthalpy[exponent=\circ,subscript=right,unit=kJ](f){-92.5}

$\Delta H_{\mathrm{f}}^\circ = \SI{-92.5}{kJ}$

\end{document}

So you can add the normal spacing commands like \, where you want:

Code: Select all

\documentclass{article}
\usepackage{chemmacros}
\begin{document}
standard behaviour: \Enthalpy[exponent=\circ,subscript=right,unit=kJ](f){-92.5}

\newcommand*\mycirc{\raise2pt\hbox{$\scriptstyle\circ$}}
manually changed: \Enthalpy[delta={\Delta\;},exponent={\,\mycirc},subscript=right,unit=kJ](\,f){-92.5}

renewed command:
\renewstate[exponent={\,\mycirc},subscript-left=false,subscript={\,f}]{Enthalpy}{\,\mathrm{H}}{kJ}
\Enthalpy{-92.5}

\end{document}

I don't understand why you want an upright H as symbol for the enthalpy, though. It is a variable and as such typically typeset in italics as a look into any good about thermodynamics can confirm...

[josephwright]

I'd second cgneider's comments. Also, while it's common to show the 'f' as you have, it belongs with the delta (it's a change on formation). Using a circle rather than a proper standard state symbol seems rather odd when the default setting for \Enthalpy gets it right.

[ghostanime2001]

I'm typing up my homework and all the questions are like that I don't want to change every question and besides a circle is what I was taught as standard state when I was in highschool. Also How can I get the "f" to be more pronounced and obvious? For example... longer cross and a more curvy f ?