Question

2. When a 6.50 g sample of solid sodium hydroxide dissolves in 100.0 g of water in a coffee-cup calorimeter (figure 5.18 in your textbook), the temperature rises from 21.6 to 37.8 C. a. Calculate the quantity of heat (in kJ) released in the reaction (the dissolving of NaOH). b. Using the result from part a, calculate the enthalpy of the reaction for the solution of NaOH in kJ/mol NaOH.

Answer 1

(2 calorimetry & solid sodium hydronide strong electrolyte and dissolves in water. is a completely In calorimeter, absorbed Heat released by = - Heat, by solution. reaction dere to dissokie of Maoh. dron = - Isolm heat absorbed by solution, Isolna mson & Csolna a Tson. on som i massot solution += 100.0576-50), - 100.com ( Ma oH f SH 20) = 10650 Csoln & Heat Capacity of solution same as ²9.184 ilgo Water . Tseln Temperature change = (37.8-21-6). i in solution soln & = 106.509x4.18 4 Jlg oC x 1612°C 7218-65 J = 16: 26 a som = 7.2186 kJ (: 1 kg = 1000) quantity of heat released in the reaction the dissolving of MacH) ? nxn - - 980). love Sigon implies the reaction is enothermict heat releases] = |- 7.2186 KJ

b) Molar mass of mailHz (23 + 1 + 16) glance . roles i of 40 g smal Madh- 6.5g. 1 mol Madh = 6.58 x 40 g - 0.1625 mol i. Enthalpy of reaction n of Mack for the for the a solution Hron - Tron soles of mach 7:218696 - 0.1625 mal 44.42 kJ/mol