Chemical Engineering Questions and Answers – Standard Heat (Enthalpy) of Formation

This set of Basic Chemical Engineering Multiple Choice Questions & Answers (MCQs) focuses on “Standard Heat (Enthalpy) of Formation”.

1. For exothermic reactions, what is the heat of reaction?
a) Positive
b) Negative
c) Zero
d) Cannot Say
View answer

Answer: b
Explanation: In exothermic reactions, heat leaves the system, so the heat of reaction is negative.

2. For endothermic reactions, what is the heat of reaction?
a) Positive
b) Negative
c) Zero
d) Cannot Say
View answer

Answer: a
Explanation: In endothermic reactions, heat comes into the system, so the heat of reaction is positive.

3. Enthalpy of reactants is 15 J/Kg and enthalpy of products is 40 J/Kg, what is the heat of reaction?
a) -10 J/Kg
b) 10 J/Kg
c) -25 J/Kg
d) 25 J/Kg
View answer

Answer: d
Explanation: Heat of reaction = 40 – 15 = 25 J/Kg.
advertisement

4. Enthalpy of reactants is 50 J/Kg and enthalpy of products is 25 J/Kg, what is the heat of reaction?
a) -10 J/Kg
b) 10 J/Kg
c) -25 J/Kg
d) 25 J/Kg
View answer

Answer: c
Explanation: Heat of reaction = 25 – 50 = -25 J/Kg.

5. Enthalpy of reactants is 30 J/Kg and enthalpy of products is 10 J/Kg, what is the heat of reaction?
a) -20 J/Kg
b) 20 J/Kg
c) -10 J/Kg
d) 10 J/Kg
View answer

Answer: a
Explanation: Heat of reaction = 10 – 30 = -20 J/Kg.
Free 30-Day Java Certification Bootcamp is Live. Join Now!

6. Heat of formations of A, B, C, and D, are 5 J, 10 J, 15 J, and 20 J respectively, what is the heat of reaction A + 4B -> 3C + D?
a) 10 J
b) 20 J
c) 35 J
d) 45 J
View answer

Answer: b
Explanation: Heat of reaction = 20 + 3*15 – 4*10 – 5 = 20 J.

7. Heat of formations of A, B, C, and D, are 5 J, 8 J, 2 J, and 15 J respectively, what is the heat of reaction 3A + B -> 3C + 2D?
a) 9 J
b) 10 J
c) 13 J
d) 15 J
View answer

Answer: c
Explanation: Heat of reaction = 2*15 + 3*2 – 8 – 3*5 = 13 J.

8. Heat of formations of A, B, C, and D, are 1 J, 2 J, 3 J, and 4 J respectively, what is the heat of reaction 3A + 4B -> 2C + D?
a) -1 J
b) 1 J
c) 3 J
d) 6 J
View answer

Answer: a
Explanation: Heat of reaction = 4 + 2*3 – 4*2 – 3*1 = -1 J.

9. Heat of formations of A, B, C, and D, are 2 J, 5 J, 3 J, and 10 J respectively, what is the heat of reaction 4A + 5B -> 2C + 2D?
a) -10 J
b) -7 J
c) -5 J
d) 0
View answer

Answer: b
Explanation: Heat of reaction = 2*10 + 2*3 – 5*5 – 4*2 = -7 J.
advertisement

10. Heat of formations of A, B, C, and D, are 3 J, 5 J, 4 J, and 8 J respectively, what is the heat of reaction 2A + 2B -> 2C + D?
a) -5 J
b) 0
c) 5 J
d) 8 J
View answer

Answer: b
Explanation: Heat of reaction = 8 + 2*4 – 2*5 – 2*3 = 0.

11. In the reaction C + O2 -> CO2, if the heat liberated is 10 J, what is the heat of formation of CO2?
a) -10 J
b) 10 J
c) 0
d) Cannot be determined
View answer

Answer: a
Explanation: Heat of formation = -10 J.

12. In the reaction 2H2 + O2 -> 2H2O, if the heat liberated is 50 J, what is the heat of formation of H2O?
a) -25 J
b) 25 J
c) -50 J
d) 50 J
View answer

Answer: a
Explanation: Heat of formation = -50/2 = -25 J.

13. In the reaction 2N -> N2, if the heat liberated is 6 J, what is the heat of formation of N2?
a) – 6 J
b) 6 J
c) 0
d) Cannot be determined
View answer

Answer: a
Explanation: Heat of formation = -6 J.

14. In the reaction 2C + O2-> 2CO, if the heat liberated is 10 J, what is the heat of formation of CO?
a) -5 J
b) 5 J
c) -10 J
d) 10 J
View answer

Answer: a
Explanation: Heat of formation = -10/2 = -5 J.

15. In the reaction C + 2H2 -> CH4, if the heat liberated is -5 J, what is the heat of formation of CH4?
a) -5J
b) 5 J
c) 0 J
d) Cannot be determined
View answer

Answer: b
Explanation: Heat of formation = – (-5) = 5 J.

Sanfoundry Global Education & Learning Series – Basic Chemical Engineering.

To practice all areas of Basic Chemical Engineering, here is complete set of 1000+ Multiple Choice Questions and Answers.

advertisement
advertisement
Subscribe to our Newsletters (Subject-wise). Participate in the Sanfoundry Certification contest to get free Certificate of Merit. Join our social networks below and stay updated with latest contests, videos, internships and jobs!

Youtube | Telegram | LinkedIn | Instagram | Facebook | Twitter | Pinterest
Manish Bhojasia - Founder & CTO at Sanfoundry
I’m Manish - Founder and CTO at Sanfoundry. I’ve been working in tech for over 25 years, with deep focus on Linux kernel, SAN technologies, Advanced C, Full Stack and Scalable website designs.

You can connect with me on LinkedIn, watch my Youtube Masterclasses, or join my Telegram tech discussions.

If you’re in your 40s–60s and exploring new directions in your career, I also offer mentoring. Learn more here.