in one experient, a student placed 50.0ml of 1.00molar Hcl at 25.5celsius in a coffee-cup calorimeter. to this was added 50.0ml of 1.00molar NaoH solution also at 25.5celsius. the mixture was stirred, and the temperature quickly increase to a maximum of 32.2 celsius. what is the energy evolved in kilojoules per mole of Hcl?

Question

in one experient, a student placed 50.0ml of 1.00molar Hcl at 25.5celsius in a coffee-cup calorimeter. to this was added 50.0ml of 1.00molar NaoH solution also at 25.5celsius. the mixture was stirred, and the temperature quickly increase to a maximum of 32.2 celsius. what is the energy evolved in kilojoules per mole of Hcl?

Answer 1

qrxn = mcdeltaT.

You know m, c, and delta T which allows you to calculate q for the reaction. That is for 50 mL x 0.1 M = 5 millimoles or 0.005 moles. Convert to kJ/mole

Answer 2

To find the energy evolved per mole of HCl, we can use the equation:

q = m * c * ΔT

where:
q = energy evolved (in Joules)
m = mass of the solution (in grams)
c = specific heat capacity of the solution (in J/g°C)
ΔT = change in temperature (in °C)

First, let's calculate the mass of the solution. Since we added equal volumes of HCl and NaOH solutions, the total volume of the solution is 100.0 mL (50.0 mL of HCl + 50.0 mL of NaOH). But we need to convert it to grams:

1 mL of water weighs approximately 1 gram.

So, 100.0 mL of water = 100.0 grams.

Next, we need to determine the specific heat capacity of the solution. Since it is a dilute solution, we can assume the specific heat capacity of the solution is approximately the same as the specific heat of water, which is 4.18 J/g°C.

Now, we can calculate the change in temperature (ΔT):

ΔT = final temperature - initial temperature
ΔT = 32.2°C - 25.5°C
ΔT = 6.7°C

Now that we have all the values, we can calculate the energy evolved (q):

q = m * c * ΔT
q = 100.0 g * 4.18 J/g°C * 6.7°C
q = 2796.6 J

But we need to convert Joules to kilojoules:

1 kJ = 1000 J

So, the energy evolved is:

2796.6 J ÷ 1000 = 2.7966 kJ

Now, to find the energy evolved per mole of HCl, we need to calculate the number of moles of HCl used:

moles of HCl = volume * concentration
moles of HCl = 50.0 mL * (1.00 mol/L)
moles of HCl = 0.0500 mol

Finally, we can calculate the energy evolved per mole of HCl:

Energy per mole of HCl = (Energy evolved in kJ) / (moles of HCl)
Energy per mole of HCl = 2.7966 kJ / 0.0500 mol

Energy per mole of HCl ≈ 55.932 kJ/mol

Therefore, the energy evolved in kilojoules per mole of HCl is approximately 55.932 kJ/mol.