3. 50 ml (= 50 g) of 1.0 M HCl is mixed with 50 ml (= 50 g) of 1.0 M NaOH in a c
ID: 561251 • Letter: 3
Question
3. 50 ml (= 50 g) of 1.0 M HCl is mixed with 50 ml (= 50 g) of 1.0 M NaOH in a calorimeter. The initial temperature of HCI and NaOH is 25.0°C. The heat from the reaction is contained in the calorimeter to warm up the mixture, and the final temperature of the solution is 44.0· The specific heat of the solution is 4. 18 J / g °C, and the calorimeter constant Ccalorimeter= 23. 5 J / . a. Write the reaction equation. b. How many moles of HCI (or NaOH) are used in the reaction? c. Calculate the molar reaction heat AHExplanation / Answer
QQ3
a)
adcid + base= water ´salt
HCl + NaOH = H2O + NaCl
b)
total mass = 50+50 = 100 g
mol of acid = MV = 1*50*10^-3 = 0.05
c)
HRxn = Qrxn/n
-QRxn = Qsolution + Qcalorimter
-Qrxn = (m*C*dT) + (CCal*dT)
-Qrxn = (100*4.184*(44-25)) + (23.5*(44-25))
-QRxn = 8396.1
-QRxn = -8396.1 J
HRxn = Qrxn/n
HRxn = -8396.1/0.05 = -167922 J/mol = -167 kJ/mol