But in the answer options:
a) -27.4 kJ
b) -72.8 kJ
c) -78.4 kJ
d) -84.6kJ
I attempted this problem in the other way.When using the q =mcdT,I added the mass of both water and sulfuric acid.
q = (300g +10.65g)(4.184J/g.K)(6.55C)
= 8513.43 J
Then, I calculated the mole of sulfuric acid ,n = 10.65g/(98.08g/mol) = 0.1086mol
Since the question asks for heat evolved/mole of H2SO4,so
q sulfuric acid = 8513.43J/(0.1086mol)x 1 mol of H2SO4
= -78.4 kJ(option c)
Need detailed explanation.Thank you.
That looks good to me. I ignored the H2SO4 when I responded to your question earlier; it appears that is not acceptable.
To solve this problem, you need to calculate the heat evolved by the sulfuric acid using the equation q = mcdT, where q is the heat evolved, m is the mass, c is the specific heat capacity, and dT is the change in temperature.
First, calculate the heat evolved by the water and sulfuric acid combined:
q = (mass of water + mass of sulfuric acid) * c * dT
= (300g + 10.65g) * 4.184J/g.K * 6.55°C
= 3119.28 J
Next, you need to find the number of moles of sulfuric acid. To do this, divide the mass of sulfuric acid by its molar mass:
n = mass / molar mass
= 10.65g / 98.08g/mol
= 0.1086 mol
Finally, divide the heat evolved by the number of moles of sulfuric acid to find the heat evolved per mole:
q sulfuric acid = q / n
= 3119.28 J / 0.1086 mol
≈ -78.4 kJ
Therefore, the correct option is c) -78.4 kJ.