A 100.00 ml of volume of 0.500 M HCl was mixed with 100.00 ml of 0.500 M KOH in a constant pressure calorimeter. The initial temperature of individual acid and base was 23.0 oC. The final temperature after mixing was 25.5 oC. The specific heat of the solution was 3.97 J g-1 oC-1 Assume the density of the solution is 1.00 g mL-1
a) Calculate the heat of the reaction in kJ. (Be sure to use signs correctly.)
To calculate the heat of the reaction, we can use the formula:
q = m × c × ΔT
Where:
q = heat of the reaction (in joules)
m = mass of the solution (in grams)
c = specific heat of the solution (in J g-1 oC-1)
ΔT = change in temperature (final temperature - initial temperature)
First, we need to find the mass of the solution. To do this, we can calculate the total volume of the solution. Since the density of the solution is 1.00 g mL-1, the mass will be equal to the volume.
Total volume of solution = volume of HCl + volume of KOH
Total volume of solution = 100.00 ml + 100.00 ml
Total volume of solution = 200.00 ml
Now, let's convert the volume to grams:
Mass of the solution = Volume × Density
Mass of the solution = 200.00 ml × 1.00 g/mL
Mass of the solution = 200.00 g
Next, we can calculate the change in temperature:
ΔT = final temperature - initial temperature
ΔT = 25.5 oC - 23.0 oC
ΔT = 2.5 oC
Finally, we can calculate the heat of the reaction:
q = m × c × ΔT
q = 200.00 g × 3.97 J g-1 oC-1 × 2.5 oC
To convert the result to kJ, we divide by 1000:
q = (200.00 g × 3.97 J g-1 oC-1 × 2.5 oC) / 1000
q = 1990 J / 1000
q = 1.99 kJ (rounded to two decimal places)
Therefore, the heat of the reaction is 1.99 kJ (remember to include the correct sign).
To calculate the heat of the reaction, we can use the equation:
q = m * c * ΔT
where:
- q is the heat released or absorbed by the reaction,
- m is the mass of the solution,
- c is the specific heat capacity of the solution,
- ΔT is the change in temperature.
First, let's calculate the mass of the solution. The volume of the solution is given as 100.00 mL, and the density is given as 1.00 g mL-1, so:
mass = volume * density
mass = 100.00 mL * 1.00 g mL-1
mass = 100.00 g
Next, we need to calculate the change in temperature (ΔT):
ΔT = final temperature - initial temperature
ΔT = 25.5 oC - 23.0 oC
ΔT = 2.5 oC
Now, we can calculate the heat of the reaction (q):
q = mass * c * ΔT
q = 100.00 g * 3.97 J g-1 oC-1 * 2.5 oC
To convert the result to kilojoules (kJ), we divide the value by 1000:
q = (100.00 g * 3.97 J g-1 oC-1 * 2.5 oC) / 1000
q = 0.9925 kJ
Therefore, the heat of the reaction is 0.9925 kJ.
-1.985
q = mass x specific heat x ((Tfinal-Tinitial0
You know mass is 200 g
Specific heat is given in J
You have Tfinal and Tinitial.
Substitute and solve for q. Remember this is an exothermic reaction (it gives off heat), so place a negative sign for the number is J. Convert to kJ.
Most problems I've seen like this ask for kJ/mol but you only asked for kJ of heat so I stopped there.