Respuesta :
Answer:
1.45 kilo joules of heat is produced when 100 mL of 0.250 M HCl and 200 mL of 0.150 M NaOH.
1.15°C is the temperature increase.
Step-by-step explanation:
[tex]HCl+NaOH\rightarrow NaCl+H_2O[/tex] ,ΔH°=-58 kJ/mol
[tex]Molarity=\frac{Moles}{Volume (L)}[/tex]
Molarity of HCl = 0.250 M
Volume of HCl = 100 ml = 0.1 L
Moles of HCl = n
[tex]n=0.250\times 0.1 L=0.0250 mol[/tex]
Molarity of NaOH= 0.150 M
Volume of NaOH= 200 ml = 0.2 L
Moles of NaOH= n'
[tex]n'=0.150\times 0.2 L=0.030 mol[/tex]
According to reaction, 1 mol of HCl reacts with 1 mol of NaOH. Then 0.0250 mole of HCl will reacts with 0.0250 mol of NaOH.
[tex]\frac{1}{1}\times 0.0250 mol=0.0250 mol[/tex] of NaOH
As we can see that moles of NaOH are in excess.Hence, excessive agent.
The enthalpy of the reaction = ΔH°=-58 kJ/mol
Energy released when 0.0250 moles of HCl reacted with 0.0250 moles of NaOH:
[tex]Q=\Delta H^o\times 0.0250 mol=-58 kJ/mol\times 0.0250 mol=-1.45 kJ[/tex]
(Negative sign indicates that heat is liberated.)
Mass of the HCL solution = m
Volume of HCl ,v= 100 ml
Density of HCl solution = d = 1.00 g/mL
[tex]m=d\times v=1.00 g/mL\times 100 mL=100 g[/tex]
Mass of NaOH solution = m'
Volume of NaOH ,v' = 200 ml
Density of NaOH solution = d' = 1.00 g/mL
[tex]m'=d'\times v'=1.00 g/mL\times 200 mL=200 g[/tex]
Mass of the solution after mixing,M = m + m' = 100 g + 200 g = 300 g
Heat absorbed by the final solution formed after mixing = Q'
Heat absorbed by the final solution formed after mixing = Heat released during reaction
Q' = -Q = -(-1.45 kJ)= 1.45 kJ=1450 J (1kJ = 1000 J)
Q' = mcΔT
generally, m = mass of the substance
c = specific heat of the substance
ΔT = Change in temperature
Specific heat capacity of the product formed after mixing = c = 4.19 J/g°C
Mass of the resulting mix = 300 g
ΔT = ?
[tex]1450 J=300g\times 4.19 J/g^oC\times \Delta T[/tex]
[tex]\Delta T=\frac{1450 J}{300g\times 4.19 J/g^oC}[/tex]
[tex]\Delta T=1.15^oC[/tex]
1.15°C is the temperature increase.
