Solving Energy Balance Problems

Question 1
Marks : +2 | -2
Pass Ratio : 100%
Two feeds, F1 with H = 10 J/mole and 5 moles with H = 20 J/mole, if the mole of products is 10 what is the enthalpy of products?
10 J/mole
15 J/mole
20 J/mole
25 J/mole
Explanation:
10*5 + 5*20 = 10*H, => H = 15 J/mole.
Question 2
Marks : +2 | -2
Pass Ratio : 100%
Two feeds, F1 with H = 10 J/mole and F2 with H = 25 J/mole, and product 15 moles with H = 15 J/mole, what is the F2?
5 mole
10 mole
15 mole
20 mole
Explanation:
Energy balance: 10*F1 + 25*F2 = 15*15, => F1 + F2 = 15, => F2 = 5 mole.
Question 3
Marks : +2 | -2
Pass Ratio : 100%
Two feeds, 15 moles with H = 10 J/mole and 10 with H = 20 J/mole, what is the enthalpy of products?
8 J/mole
12 J/mole
18 J/mole
25 J/mole
Explanation:
25*H = 15*10 + 10*20, => H = 18 J/mole.
Question 4
Marks : +2 | -2
Pass Ratio : 100%
In a reaction, the feed is 10 moles of 0.1 glucose and 0.9 water, and another feed of 5 moles of 0.2 glucose and 0.8 water, what is the total moles of product?
5
10
15
20
Explanation:
Total moles of products = 10 + 5 = 15.
Question 5
Marks : +2 | -2
Pass Ratio : 100%
Two feeds, 10 moles with H = 10 J/mole and 5 with H = 25 J/mole, what is the enthalpy of products?
5 J/mole
10 J/mole
15 J/mole
20 J/mole
Explanation:
Energy balance: 10*10 + 5*25 = 15*H, => H = 15 J/mole.
Question 6
Marks : +2 | -2
Pass Ratio : 100%
Two feeds, F1 with H = 10 J/mole and F2 with H = 20 J/mole, and product 10 moles with H = 15 J/mole, what is the F1?
5 mole
10 mole
15 mole
20 mole
Explanation:
Energy balance: 10*F1 + 20*F2 = 10*15, => F1 + F2 = 10, => F1 = 5 mole.
Question 7
Marks : +2 | -2
Pass Ratio : 100%
In a reaction the feed is 10 moles of 0.1 glucose and 0.9 water, and another feed of 5 moles of 0.4 glucose and 0.6 water, what is the fraction of glucose in the products?
0.2
0.4
0.6
0.8
Explanation:
Total moles of products = 10 + 5 = 15, glucose balance: 0.1*10 + 0.4*5 = x*15, => x = 0.2.
Question 8
Marks : +2 | -2
Pass Ratio : 100%
In a reaction the feed is 10 moles of 0.1 glucose and 0.9 water, and another feed of 5 moles of 0.4 glucose and 0.6 water, what is the fraction of water in the products?
0.2
0.4
0.6
0.8
Explanation:
Total moles of products = 10 + 5 = 15, water balance: 0.9*10 + 0.6*5 = x*15, => x = 0.8.
Question 9
Marks : +2 | -2
Pass Ratio : 100%
In a reaction the feed is 5 moles of 0.5 glucose and 0.5 sucrose, and another feed of 15 moles of 0.3 glucose and 0.7 sucrose, what is the fraction of glucose in the products?
0.35
0.45
0.75
0.95
Explanation:
Glucose balance: 5*0.5 + 15*0.3 = x*20, => x = 0.35.
Question 10
Marks : +2 | -2
Pass Ratio : 100%
Enthalpy of a stream is which function of temperature and pressure?
Explicit
Implicit
Cannot say
None of the mentioned
Explanation:
Enthalpy of a stream is an explicit function of temperature and pressure.