Given the thermochemical equation 2SO2(g) + O2(g) → 2SO3(g), ΔH= -198 kJ/mol, how much heat is evolved when 600. g of SO2 is burned?
A. 5.46 x 10-2 kJ
B. 928 kJ
C. 1.85 x 103 kJ
D. 59,400 kJ
E. 3.71 x 103 kJ
198 kJ/mol x (600/64) = ?
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To calculate the heat evolved when 600. g of SO2 is burned, we need to use the thermochemical equation and the molar mass of SO2.
Step 1: Calculate the number of moles of SO2
Molar mass of SO2 = 32.07 g/mol + 2(16.00 g/mol) = 64.07 g/mol
Moles of SO2 = mass / molar mass
Moles of SO2 = 600 g / 64.07 g/mol
Step 2: Use the stoichiometry of the equation to determine the moles of SO3 produced
From the balanced equation, we see that 2 moles of SO2 produce 2 moles of SO3.
So, moles of SO3 = moles of SO2
Step 3: Calculate the heat evolved
ΔH = -198 kJ/mol
Heat evolved = moles of SO2 * ΔH
Heat evolved = (600 g / 64.07 g/mol) * -198 kJ/mol
Heat evolved = -1851.67 kJ
Since the heat evolved is typically given as a positive value, we take the absolute value of -1851.67 kJ.
Therefore, the correct answer is:
C. 1.85 x 10³ kJ
To calculate the amount of heat evolved when 600 g of SO2 is burned, we can use the equation:
q = (m × ΔH) / M
where:
q is the heat evolved (in kJ)
m is the mass of SO2 (in g)
ΔH is the enthalpy change (in kJ/mol)
M is the molar mass of SO2 (in g/mol)
First, calculate the molar mass of SO2:
M(S) = 32.07 g/mol
M(O) = 16.00 g/mol
M(SO2) = 32.07 g/mol + 2 × 16.00 g/mol = 64.07 g/mol
Next, convert the given mass of SO2 from grams to moles:
moles of SO2 = mass (g) / M(SO2) = 600 g / 64.07 g/mol ≈ 9.366 mol
Now, we can substitute the values into the equation:
q = (9.366 mol × -198 kJ/mol) / 1 mol ≈ -1851.9 kJ
Since heat is a form of energy and can't be negative, we take the absolute value:
q ≈ 1851.9 kJ
Therefore, the heat evolved when 600 g of SO2 is burned is approximately 1851.9 kJ.
The closest answer choice is C. 1.85 x 10^3 kJ.