When 5.00 g of NaOH(s) are added to 100 g of water using a calorimeter, the temperature rises from 25.0 to 37.5 °C. Calculate the molar heat of solution.
NaOH(s)--->Na(aq)+OH(aq)
Assume that the specific heat capacity of water is 4.18 J/gK and that of the NaOH(aq) solution is the same.
I worked this exact problem an hour or so ago. Have you found it. If not I will look and attach a link.
To calculate the molar heat of solution, we need to use the formula:
q = m * c * ΔT
where:
q is the heat gained or lost by the system,
m is the mass of the substance,
c is the specific heat capacity of the substance, and
ΔT is the change in temperature.
Step 1: Calculate the heat gained by the water.
First, we need to calculate the heat gained by the water in the calorimeter. We can use the formula mentioned above, where:
m = mass of water = 100 g
c = specific heat capacity of water = 4.18 J/gK
ΔT = change in temperature = (final temperature - initial temperature) = (37.5 °C - 25.0 °C)
q_water = m * c * ΔT
q_water = 100 g * 4.18 J/gK * (37.5 °C - 25.0 °C)
Step 2: Calculate the heat lost by the NaOH.
Next, we need to calculate the heat lost by the NaOH as it dissolves. We know that the temperature rose due to the exothermic process of the NaOH dissolving. Therefore, the heat lost by the NaOH is equal in magnitude but opposite in sign to the heat gained by the water.
q_NaOH = -q_water
Step 3: Calculate the moles of NaOH.
To calculate the molar heat of solution, we need to determine the moles of NaOH used. We can use the molar mass of NaOH to do this calculation. The molar mass of NaOH is 22.99 g/mol (for Na) + 16.00 g/mol (for O) + 1.01 g/mol (for H).
moles_NaOH = mass_NaOH / molar mass_NaOH
moles_NaOH = 5.00 g / (22.99 g/mol + 16.00 g/mol + 1.01 g/mol)
Step 4: Calculate the molar heat of solution.
Finally, we can calculate the molar heat of solution by dividing the heat lost by the NaOH by the moles of NaOH used.
molar heat of solution = q_NaOH / moles_NaOH
Now that we have explained the step-by-step process, we can plug in the values and calculate the molar heat of solution.