MEB multiple choice

The heat of reaction remains the same even if stoichiometric coefficients are changed

• True

• False

Why do heats of reaction change if different phases are given for products and reactants?

• The heat of reaction must account for the phase change

• The reaction occurs fundamentally differently and has a completely different heat of reaction if different phases are involved

• Phases do not affect the heat of reaction

What conditions are used for the standard heat of reaction?

• It depends on the reaction

• 0 C and 1 atm

• 25 C and 1 atm

• 20 C and 1 atm

At the conditions of interest, the heat of reaction for the equation A + 2B -> C is -140 kJ. What is the enthalpy change in kJ if 2 moles of A are consumed in the reaction?

• 140 kJ

• -140 kJ

• 280 kJ

• -280 kJ

At the conditions of interest, the heat of reaction for the equation 2A + 3B -> is -100 kJ. What is the enthalpy change in kJ if 9 moles of B are consumed in the reaction?

• -100 kJ

• 300 kJ

• -300 kJ

• 900 kJ

What is the main problem with using a calorimeter to determine heat of reaction?

• They are hard to construct and operate

• It can be hard to isolate the reaction of interest

• Calories are not an SI unit

Given the following reactions, what is the enthalpy change for the reaction 3D -> A + 3B + 5C in kJ?

(1) A -> 3B + C, Hr = 100 kJ

(2) A + C -> D + B, Hr = -200 kJ

• -600 kJ

• -300 kJ

• 100 kJ

• 800 kJ

Given the following reactions, what is the enthalpy change for the reaction 4A + 2C -> 3D + 6B in kJ?

(1) A -> 3B + C, Hr = 100 kJ

(2) A+ C -> D + B, Hr = -200 kJ

• 800 kJ

• -500 kJ

• 300 kJ

• 400 kJ

Given the following data, what is the heat of reaction for A (g) + B(g) + O₂ (g) -> C (g) in kJ?

• 255 kJ

• 180 kJ

• -150 kJ

• -175 kJ

What expression would give the heat of reaction for the reaction CH₄ (g) + Cl₂ (g) -> CH₃Cl (g) + HCl (g)?

• A

• B

• C

• D

• E