During an experiment, a student adds 1.23 g of CaO to 200.0 mL of 0.500 M HCl. The student observes a temperature increase of 5.10 °C. Assuming the solution\'s final volume is 200.0 mL, the density if 1.00 g/mL, and the heat capacity is 4.184 J/(g·°C), calculate the heat of the reaction, ΔHrxn.
i know i need to use the equations q=mcdeltaT
and delta H= q/n but i keep getting the wrong answer. also which one is the limiting reactant...
To calculate the heat of the reaction, ΔHrxn, we can use the equation:
ΔHrxn = q / n
Where q is the heat absorbed or released during the reaction, and n is the number of moles of the limiting reactant. In this case, we need to determine the heat (q) absorbed or released during the reaction.
To calculate the heat (q), we can use the equation:
q = m x C x ΔT
Where m is the mass of the solution in grams, C is the specific heat capacity in J/(g·°C), and ΔT is the change in temperature in °C.
Let's calculate the heat (q) first, and then use it to find the heat of the reaction, ΔHrxn.
1. Calculate the mass of the solution:
Mass = volume x density
Mass = 200.0 mL x 1.00 g/mL
Mass = 200.0 g
2. Calculate the heat (q):
q = m x C x ΔT
q = 200.0 g x 4.184 J/(g·°C) x 5.10 °C
q = 4233.36 J
3. Now, we need to calculate the number of moles of the limiting reactant (CaO). To do this, we need to convert the mass of CaO to moles using its molar mass.
The molar mass of CaO is 56.08 g/mol. We can use this to convert the mass of CaO to moles:
Moles of CaO = Mass of CaO / Molar mass of CaO
Moles of CaO = 1.23 g / 56.08 g/mol
Moles of CaO = 0.021933 mol
4. Finally, we can calculate the heat of the reaction (ΔHrxn):
ΔHrxn = q / n
ΔHrxn = 4233.36 J / 0.021933 mol
ΔHrxn = 192,892.12 J/mol
Therefore, the heat of the reaction, ΔHrxn, is 192,892.12 J/mol.