Answered

A reaction of 100mL of 1.35 M HCl and 100mL of 1.76 M NaOH is monitored and the following
temperatures were recorded: starting temperature = 24.6 C; and final temperature = 38.8 C.
Calculate the AH of this reaction.

A) -92142
J/Mole
B) -12439.2
J/Mole
C) 876
J/Mole

Answer :

Answer:  [tex]\Delta H[/tex] for the reaction is 87935 J

Explanation:

Molarity of a solution is defined as the number of moles of solute dissolved per Liter of the solution.

[tex]Molarity=\frac{moles}{\text {Volume in L}}[/tex]

[tex]moles of HCl[/tex]=[tex]Molarity\times {\text {Volume in L}}=1.35\times 0.01=0.135moles[/tex]

[tex]moles of NaOH[/tex]= [tex]Molarity\times {\text {Volume in L}}=1.76\times 0.01=0.176moles[/tex]

As 1 mole of HCl neutralizes 1 mole of NaOH

0.135 moles of HCl will neutralize = 0.135 mole of NaOH

Thus HCl is the limiting reagent.

[tex]Q=m\times c\times \Delta T=m\times c\times (T_{final}-T_{initial})[/tex]

Q = Heat absorbed by water = ?

m = mass of water = 200 g    (volume of water=200ml, density of wtaer = 1 g/ml)

c = specific heat capacity = [tex]4.18 J/g^0C[/tex]

Initial temperature of water = = 24.6°C

Final temperature of water=  = 38.8 °C

[tex]Q=200\times 4.18\times (38.8-24.6)[/tex]

[tex]Q=11871.2J[/tex]

Thus heat released by 0.135 moles is = -11871.2 J

heat released by 1 mole is =[tex]\frac{-11871.2 J}{0.135}\times 1=-87935J[/tex]

mickymike92

The heat of reaction, ΔH is 87935 J

Molarity and Heat of Reaction ΔH

  • Molarity of a solution is defined as the number of moles of solute dissolved per Liter of the solution.
  • The heat of reaction ΔH, is the amount of heat evolved or absorbed when a chemical reaction occurs between molar quantities of the reactants as represented in the equation of reaction.

Equation of reaction between HCl and NaOH is given below:

  • HCl + NaOH ----> NaCl + H₂O

Molarity = number of mole/volume

Number of moles = molarity * volume

Number of moles of  HCl = 1.35 M * 0.1 L = 0.135 moles

Moles of NaOH = 1.76 M * 0.1 L = 0.176 moles

1 mole of HCl neutralizes 1 mole of NaOH

  • Therefore, 0.135 moles of HCl will neutralize 0.135 mole of NaOH
  • Therefore, NaOH is in excess and  HCl is the limiting reagent.

Calculating the quantity of heat evolved:

  • Q = mcΔT

where m is mass, c is specific heat capacity, ΔT is temperature change

  • Quantity of heat evolved by reaction = Heat absorbed by water

Heat absorbed by water, Q = mcΔT

mass of water = density * volume

density of water = 1 g/mL

volume of water = 200 mL

mass of water = 1 g/mL * 200 mL

mass of water = 200 g

specific heat capacity of water, c = 4.18 J/g°C

  • ΔT = final temperature of water - initial temperature of water

Initial temperature of water = = 24.6°C

Final temperature of water=  = 38.8 °C

ΔT = 38.8 - 24.6 = 13.7°C

Q = 200 g * 4.18 J/g°C * 14.2°c

Q =  11871.2 J

Therefore, heat released by 0.135 moles is = -11871.2 J

Heat released by 1 mole = 11871.2 * 1/0.135

Heat released by 1 mole = 87935 J

Therefore, the heat of reaction, ΔH is 87935 J

Learn more about heat of reaction at: https://brainly.com/question/18721983

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