A student mixed 75.0 mL of water containing 0.75 mol HCl at 25�C with 75.0 mL of water containing 0.75 mol of NaOH at 25�C in a foam cup calorimeter. The temperature of the resulting solution increased to 35�C. How much heat in kilojoules was released by this reaction?
Cwater � 4.18 J/gp�C
To calculate the heat released by the reaction, we can use the equation:
q = m * C * ΔT
where:
q is the heat released (in joules),
m is the mass of the solution (in grams),
C is the specific heat capacity of water (4.18 J/gp°C), and
ΔT is the change in temperature (in °C).
First, let's calculate the mass of the solution. Since the solutions were mixed in equal amounts, the total volume of the solution will be 75.0 mL + 75.0 mL = 150.0 mL.
The density of water is approximately 1 g/mL, so the mass of the solution is given by:
mass = volume * density
mass = 150.0 mL * 1 g/mL = 150.0 g
Next, let's calculate the change in temperature:
ΔT = final temperature - initial temperature
ΔT = 35°C - 25°C = 10°C
Now, we can plug these values into the equation to calculate the heat released:
q = 150.0 g * 4.18 J/gp°C * 10°C
q = 6270 J
Finally, let's convert the heat from joules to kilojoules:
q = 6270 J * (1 kJ/1000 J)
q = 6.27 kJ
Therefore, the heat released by the reaction is 6.27 kilojoules.
To find the amount of heat released by the reaction, we can use the equation:
q = m * C * ΔT
Where:
q = heat released or absorbed by the reaction (in Joules)
m = mass of the solution (in grams)
C = specific heat capacity of water (in J/g°C)
ΔT = change in temperature of the solution (in °C)
First, let's find the mass of the solution. Since we added an equal amount of water (75.0 mL) to both the HCl and NaOH solutions, the total volume of the solution is 75.0 mL + 75.0 mL = 150.0 mL.
To convert this to grams, we need to multiply by the density of water, which is approximately 1 g/mL.
Mass of the solution = Volume * Density
Mass of the solution = 150.0 mL * 1 g/mL
Mass of the solution = 150.0 g
Now, we can calculate the heat released:
q = m * C * ΔT
q = 150.0 g * 4.18 J/g°C * (35°C - 25°C)
q = 150.0 * 4.18 * 10 * 10 J
To convert Joules to kilojoules, we divide by 1000:
q = (150.0 * 4.18 * 10 * 10) / 1000 kJ
q = 6.27 kJ
Therefore, the reaction released 6.27 kilojoules of heat.
You had 150 mL water and I suppose the density is 1.0 g/mL so this is 150 g.
q = heat released = mass water x specific heat H2O x (Tfinal-Tinitial)
If you use grams and 4.18 J/g*c, the answer will come out in joules and you will need to convert to kJ.