C_7 H_16(l) + a[O_2 + 3.76 N_2] rightarrow b CO_2 + c H_2O + dN_2 + eO_2 The coe
ID: 524707 • Letter: C
Question
C_7 H_16(l) + a[O_2 + 3.76 N_2] rightarrow b CO_2 + c H_2O + dN_2 + eO_2 The coefficient c for a combustion reaction with 100% theoretical air for O_2 is a. 22. b. 11 c. 0 d. none of the above. The coefficient a for a combustion reaction with 100% theoretical air for O_2 is a. 22. b. 11 c. 0 d. none of the above. The coefficient a for the combustion reaction with 300% theoretical air for N_2 is a. 11.00 b. 22.00 c. 33.00 d. cannot be determined. The air to fuel ratio expressed in kg air to kg fuel for a combustion reaction with 300% theoretical air is a. 15.1 b. 45.51 c. 157.08 d. none of the above. The air to fuel ratio expressed in moles of air to moles of fuel for a combustion reaction with 300% theoretical air is a. 15.1 b. 45.51 c. 157.08 d. none of the above.Explanation / Answer
There are 7 atoms of Carbon and 16 atoms of Hydrogen in C7H16.
Accordingly
C7H16 + 11O2-------à 7CO2 + 8H2O.
Air contains 21% O2 and 79% N2. Moles of air 11/0.21= 52.4
For 100% theoretical air, the coefficient is 11. ( b is correct).
Question 92 is same as 91. The answer is 11 ( b is correct).
93. when 300% theoretical air is supplied, the coefficient of O2 become 3*11=33 ( c is correct
When 300% air is supplied, moles of air supplied= 52.4*3= 157.2 moles. Mass of air= 157.2*29 ( 29vis the molar mass of air) =4559
Moles of C7H16= 1, mass of heptanes= moles* molar mass= 1*100= 100
Air to fuel ratio = 4559/100= 45.59 kg of air/ kg of Fuel.( b is correct)
Air to fuel ratio = 157.2/1= 157.2 moles of air/mole of fuel ( c is correct).