[qstong0601]

A 135 g sample of dilute hydrochloric acid is placed in a copper calorimeter with a mass of 465 g. The temperature of the acid and calorimeter is 11.7 0C.  A mass of 5.00 g of aluminum metal is reacted with the acid.  After the reaction has ceased, the temperature is 22.3 0C.  Calculate the molar enthalpy change for the reaction:

Al(s)  + 3 HCl(aq)  AlCl3 (aq)  + 3/2 H2 (g)

Assume that the dilute hydrochloric acid has the same specific heat as water.

first we need to figure out the heat that the surrounding absorbed. my question is that what the surrounding should be in this question? the water in dilute hydrochloric acid or the water in AlCl3 aqeous solution?