An adiabatic solution calorimeter and measurements of a standard reaction for solution calorimetry

Abstract

T his paper disc usses in detai l th e de sign, co nstruction , and perfor mance of the va c uum jacketed , adiabatic so lution calorimeter whi c h was used for the work in th e ce rt ifica tion of two NBS Standard Refe re nce Mate rials for so lution calorimetry. As a test for the calurirnetri c precis ion th e fo llowin g ent hal pi es uf reaction we re meas ure d (refe rred to th e mass or moles of H 2S0 4 , 8 H 20 ) : Key words: Adiabatic so lution calorim eter; enthalpy of reactiun of H 2S0 4 in aqueous NaOH; H 2S0 4, e nth alpy of reaction in NaOH(aq); heat of reaction of H 2 S04 in aqueous NaOH; heat of solution of H2S04 in aqueo us NaOH; solution calorimetry; thermochem istry.

Enthalpies of reaction of tris(hydroxymethyl)aminomethane in HCl(aq) and in NaOH(aq)

“…Recently it was issued by the National Bureau of Standards as a standard reference material for solution calorim e try , SRM 724 and 724a. 2 The expe rime ntal work whic h is the basis for the certified e nthalpy valu es for thi s standard reference material is disc uss ed in sections 3.3 and 3.4.…”

Systematic errors in an isoperibol solution calorimeter measured with standard reference reactions

“…Results were obtained in this system using various calorimetric procedures in co mmon use at high and low stirring rates. These results are compared with those obtained In a platinum-lined silver, vacuum-jacketed, adiabatic solution calorimeter [6,7,9] for which it has been demonstrated [9] that negligible corrections for heat transfer with the environment are required .…”

“…Therefore, if the recommended procedures are followed, the sources of error identified here should be minimized; this can be confirmed by measurements of a standard reference reaction [6,7,9,10].…”

Enthalpies of Solution of the Nucleic Acid Bases. 6. Guanine in Aqueous HCl and NaOH, and Guanine Hydrochlorides in Aqueous HCl

“…The calorimeter, procedures used for measurements, electrical measuring instruments, and corrections to the experimental data have been described [13,15]. Reaction period is the elapsed time between the initiation of the reaction and the beginning of the rating period which follows the reaction.…”

“…Uncertainties are expressed as standard deviations except as otherwise noted. The weights in air for all crystalline samples and solutions have been corrected to vacuum (mass) as described previously [13]. For calculating buoyancy factors, densities for the aqueous HCI and NaOH solutions were obtained from the Handbook of Chemistry and Physics [14].…”