# Chemistry

posted by
**Chen**
.

A student conducts an experiment to determine the enthalpy of neutralization for phosphoric acid

reacting with sodium hydroxide. The student combines 25.0 mL of equimolar solutions of acid and

base, both having an initial temperature of 22.5 °C, in an open polystyrene calorimeter. Each

solution has a density of 1.00 g/mL and a specific heat of 4.18

J

g • °C

. The student collects data until

a maximum temperature of 26.4 °C is reached.

(a) What assumption is the student allowed to make?

(b) Explain how the student knows data collection is complete.

(c) Calculate the qrxn for the neutralization reaction.

(d) Is the reaction exothermic or endothermic? Justify your answer.

(e) Calculate the ΔHneut

if the initial molarities of both solutions is equal to 0.80 M. Be sure to

report your answer with the correct sign and units.