Question

An experiment is to be performed to determine the standard molar enthalpy of neutralization of a strong acid by a strong base. Standard laboratory equipment and a supply of standardized 1.00-molar HCl and standardized 1.00-molar NaOH are available.

(a) What equipment would be needed?

(b) What measurements should be taken?

(c) Without performing calculations, describe how the resulting data should be used to obtain the standard molar enthalpy of neutralization.

(d) When a class of students performed this experiment, the average of the results was -55.0 kilojoules per mole. The accepted value for the standard molar enthalpy of neutralization of a strong acid by a strong base -57.7 kilojoules per mole. Propose two likely sources of experimental error that could account for the result obtained by the class.

Answer 1

(a) What equipment would be needed?

Titration --> burete, beaker, acid//base

(b) What measurements should be taken?

Take masurements of:

Volume of base, Concentration of NaOH, volume of a acid

(c) Without performing calculations, describe how the resulting data should be used to obtain the standard molar enthalpy of neutralization.

This will be a titration curve, so expect a low pH due to acid and a high change in pH when equivalence point is achieved

(d) When a class of students performed this experiment, the average of the results was -55.0 kilojoules per mole. The accepted value for the standard molar enthalpy of neutralization of a strong acid by a strong base -57.7 kilojoules per mole. Propose two likely sources of experimental error that could account for the result obtained by the class.

- Incorrect standarization of base

- Excess volumen used when equivalence point is reached