Question

Part 1: You wish to determine ΔH of the following reaction. CS2(ℓ) + 3O2(g) ---> CO2(g) + 2SO2(g) Previous research indicates the following ΔH reaction values: C(s) + O2(g) ---> CO2(g) ΔH = -393.5 kJ/mol S(s) + O2(g) ---> SO2(g) ΔH = -296.8 kJ/mol C(s) + 2S(s) ---> CS2(ℓ) ΔH = +87.9 kJ/mol In order to match the coefficients in the desired reaction, which transformation(s) will you do to the reaction forming CO2? And how will ΔH change?

A) Flip, changing the sign of ΔH

B) Multiply, and multiplying the value of ΔH

C)Flip and multiply, multiplying the value of ΔH and changing the sign

D) Nothing, with no change to ΔH

Part 2: You wish to determine ΔH of the following reaction. CS2(ℓ) + 3O2(g) ---> CO2(g) + 2SO2(g) Previous research indicates the following ΔH reaction values: C(s) + O2(g) ---> CO2(g) ΔH = -393.5 kJ/mol S(s) + O2(g) ---> SO2(g) ΔH = -296.8 kJ/mol C(s) + 2S(s) ---> CS2(ℓ) ΔH = +87.9 kJ/mol In order to match the coefficients in the desired reaction, which transformation(s) will you do to the reaction forming SO2? And how will ΔH change?

A) Flip and multiply, multiplying the value of ΔH and changing the sign

B) Flip, changing the sign of ΔH C) Multiply, and multiplying the value of ΔH

D) Nothing, with no change to ΔH

Part 3: You wish to determine ΔH of the following reaction. CS2(ℓ) + 3O2(g) ---> CO2(g) + 2SO2(g) Previous research indicates the following ΔH reaction values: C(s) + O2(g) ---> CO2(g) ΔH = -393.5 kJ/mol S(s) + O2(g) ---> SO2(g) ΔH = -296.8 kJ/mol C(s) + 2S(s) ---> CS2(ℓ) ΔH = +87.9 kJ/mol In order to match the coefficients in the desired reaction, which transformation(s) will you do to the reaction forming CS2? And how will ΔH change?

A) Flip, changing the sign of ΔH

B) Multiply, and multiplying the value of ΔH

C) Nothing, with no change to ΔH

D) Flip and multiply, multiplying the value of ΔH and changing the sign

Part 4: You will notice that multiple reactions in the above table contain O2. Normally, if a substance is represented in multiple locations, we balance that substance last. Change the three reactions according to your answers in parts 1-3 and add the reactions together (adding reactants with reactants on one side of the arrow and products with products on the opposite side of the arrow). Cancel any substances that are the same on both sides of the reaction. Add together any substances that are on the same side of the reaction. After you have done so, what is the coefficient in front of O2?

Part 5: Now, sum up the ΔH values according to the transformations in parts 1-3. What is the ΔH of the desired reaction?

Answer 1