In this reaction solid NaOH is added to approximately 100 mL of 0.500 mol/L HCl.
Trial 1: 2.02 g of solid NaOH is added to 102.0 mL of the HCl solution. The temperature goes from 22.00°C to 32.0°C.
Calculate the heat evolved in each trial (Q).
I'm confused on how to calculate the heat evolved in the trial. This is what I have so far:
Q = (4.200 kJ/kg oC)(0.1020 kg)(10.00 oC) = 4.284 kJ
I don't believe you have posted the entire question; however, what you have is correct so far. Personally, I would have used 4.184 for the specific heat. Most of these questions ask for the heat/mol; you have calculated the heat of the reaction as shown.
To calculate the heat evolved in the trial, you need to use the equation:
Q = m × c × ΔT
Where:
Q = heat evolved (in joules or kilojoules)
m = mass of the substance (in grams or kilograms)
c = specific heat capacity of the substance (in J/(g°C) or kJ/(kg°C))
ΔT = change in temperature (in °C or K)
In this case, you have solid NaOH reacting with HCl to form a solution, so the mass of the substance you need to use is the mass of NaOH.
Step 1: Calculating the mass of NaOH
To find the mass of NaOH, subtract the mass of the HCl solution from the total mass.
mass of NaOH = total mass - mass of HCl solution
mass of NaOH = 2.02 g - 102.0 g
mass of NaOH = -99.98 g
However, it seems like there might be an error in the given data. A negative mass value is not possible. Please double-check the values and provide the correct mass of NaOH.
Step 2: Calculating the change in temperature
The change in temperature is given as ΔT = 32.0°C - 22.00°C = 10.0°C
Step 3: Calculating the heat evolved (Q)
Now, substitute the values into the equation:
Q = m × c × ΔT
Since the mass is negative, it needs to be corrected. Also, we need the specific heat capacity (c) of the NaOH.
Please provide the correct values for the mass of NaOH and the specific heat capacity of NaOH, and I will be able to assist you further in calculating the heat evolved in the trial.