A 1000 ml sample of 0.300 M NaOH is mixed with 100.0 ml of 0.300 M HCl in a coffee cup calorimeter. If both solutions are at 20.0 °c and the final temperature of the mixture was 22.0 °c Find the heat of neutralization, AHreu in kJ/mole. Assume no heat is lost to the surroundings, the density of all solutions is 1.00 g/mL, and C, of the mixture is 4.184 J/g·°C

Respuesta :

Answer:

ΔH(neu) = 30.68 kJ/mol

Explanation:

The reaction between HCl (strong acid) and NaOH(strong base) is a neutralization reaction which yields sodium chloride 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 = 1000 ml

Volume of NaOH = 100.0 ml

Density of HCl and NaOH = 1.000 g/ml

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

[tex]Mass(NaOH) = 1.000g/ml*1000 ml = 1000 g[/tex]

[tex]Mass(HCl) = 1.000g/ml*100.0 ml = 100.0 g[/tex]

Total mass of the solutions, m = 1000 +100.0 = 1100.0 g

c = 4.184 J/g/c

T1 = 20.0C

T2 = 22.0 C

Substituting appropriate values in equation (1) gives:

[tex]q = 1100.0 g*4.184 J/gC *(22.0-20.0)C = 9204.8 J=9.205kJ[/tex]

Now, the number of moles of NaOH is:

[tex]Moles(NaOH)=Molarity(NaOH)*Volume(NaOH)= 0.300moles/L*1.000L = 0.300moles[/tex]

Enthalpy of neutralization is:

[tex]=\frac{q}{moles(NaOH)}=\frac{9.205kJ}{0.300moles}=30.68kJ/mol[/tex]