A volume of 500.0 mL of 0.220 M HCl(aq) was added to a high quality constant-pressure calorimeter containing 500.0 mL of 0.200 M NaOH(aq). Both solutions have a density of 1.000 g mL-1 and a specific heat of 4.184 J g‑1 oC-1. The temperature of the entire system rose from 25.60 °C to 26.70 °C. Calculate the heat of reaction, in kJ, per mole of NaOH(aq).

Respuesta :

Answer:

Heat of the reaction per mole of NaOH = 46.02 kJ/mol

Explanation:

The reaction between HCl (strong acid) and NaOH(strong base) is a neutralization reaction which yields a salt NaCl and water

[tex]HCl + NaOH \rightarrow NaCl + H2O[/tex]

The heat (q) of a reaction is given as:

[tex]q = m*c*\Delta T=m*c*(T2-T1)-------(1)[/tex]

where m = mass of the system

c = specific heat

T1 and T2 are the initial and final temperatures

It is given that:

Volume of HCl = 500.0 ml

Volume of NaOH = 500.0 ml

Density of HCl and NaOH = 1.000 g/ml

[tex]Mass = Density*Volume[/tex]

[tex]Mass(HCl) = Mass(NaOH) = 1.000g/ml*500.0ml = 500.0 g[/tex]

Total mass of the solutions, m = 500.0 +500.0 = 1000.0 g

c = 4.184 J/g/c

T1 = 25.6 C

T2 = 26.70 C

Substituting appropriate values in equation (1) gives:

[tex]q = 1000.0 g*4.184 J/gC *(26.7-25.6)C = 4602.4 J=4.602kJ[/tex]

Now, the number of moles of NaOH is:

[tex]Moles(NaOH)=Molarity(NaOH)*Volume(NaOH)= 0.200moles/L*0.500L = 0.100moles[/tex]

Heat of reaction/mole NaOH is:

[tex]=\frac{q}{moles(NaOH)}=\frac{4.602kJ}{0.100moles}=46.02kJ/mol[/tex]