$\mathrm{n}$-Octane gas $\left(\mathrm{C}_8 \mathrm{H}_{18}\right)$ is burned with $100$ percent excess air in a constant pressure burner. The air and fuel enter this burner steadily at standard conditions and the products of combustion leave at $257^{\circ} \mathrm{C}$. Calculate the heat transfer, in $\mathrm{kJ} / \mathrm{kg}$ fuel, during this combustion.

n-Butane fuel $\left(\mathrm{C}_{4} \mathrm{H}_{10}\right)$ is burned with the stoichiometric amount of air. Determine the mass fraction of each product. Also, calculate the mass of carbon dioxide in the products and the mass of air required per unit of fuel mass burned.

Methane $\left(\mathrm{CH}_{4}\right)$ is burned completely with the stoichiometric amount of air during a steady-flow combustion process. If both the reactants and the products are maintained at $25^{\circ} \mathrm{C}$ and $1 \mathrm{~atm}$ and the water in the products exists in the liquid form, Find the heat transfer from the combustion chamber during this process. What would your answer be if combustion were achieved with $100$ percent excess air?

n-Octane $\left(\mathrm{C}_{8} \mathrm{H}_{18}\right)$ is burned with 50 percent excess air. Calculate the mass fraction of each product and the mass of water in the products per unit mass of fuel burned. Also, calculate the mass fraction of each reactant.

A fuel is burned steadily in a combustion chamber. The combustion temperature will be the highest except when (a) the fuel is preheated. (b) the fuel is burned with a deficiency of air. (c) the air is dry. (d) the combustion chamber is well insulated. (e) the combustion is complete.

A fuel mixture of 60 percent by mass methane $\left(\mathrm{CH}_{4}\right)$ and 40 percent by mass ethanol $\left(\mathrm{C}_{2} \mathrm{H}_{6} \mathrm{O}\right)$ is burned completely with theoretical air. If the total flow rate of the fuel is 10 kg/s, determine the required flow rate of air.

A certain natural gas has the following volumetric analysis: 65 percent $\mathrm{CH}_{4},$ 8 percent $\mathrm{H}_{2},$ 18 percent $\mathrm{N}_{2},$ 3 percent $\mathrm{O}_{2},$ and 6 percent $\mathrm{CO}_{2}.$ This gas is now burned completely with the stoichiometric amount of dry air. What is the air-fuel ratio for this combustion process?

In a combustion chamber, ethane $\left(\mathrm{C}_{2} \mathrm{H}_{6}\right)$ is burned at a rate of 8 kg/h with air that enters the combustion chamber at a rate of 176 kg/h. Determine the percentage of excess air used during this process.

Methane (CH$_4$) is burned with dry air. The volumetric analysis of the products on a dry basis is 5.20 percent CO$_2$, 0.33 percent CO, 11.24 percent O$_2$, and 83.23 percent N$_2$. Determine the percentage of theoretical air used.

An equimolar mixture of carbon dioxide and water vapor at 1 atm and $60^{\circ} \mathrm{C}$ enters a dehumidifying section where all of the water vapor is condensed and removed from the mixture, and the carbon dioxide leaves at 1 atm and $60^{\circ} \mathrm{C}.$ The entropy change of carbon dioxide in the dehumidifying section is (a) $-2.8\ \mathrm{kJ} / \mathrm{kg} \cdot \mathrm{K}$ (b) $-0.13\ \mathrm{k} / \mathrm{kg} \cdot \mathrm{k}$ (c) 0 (d) $0.13\ \mathrm{kJ} / \mathrm{kg} \cdot \mathrm{K}$ (e) $2.8\ \mathrm{kJ} / \mathrm{kg} \cdot \mathrm{K}$

Is the air-fuel ratio expressed on a mole basis identical to the air-fuel ratio expressed on a mass basis?

Butane $\left(\mathrm{C}_{4} \mathrm{H}_{10}\right)$ is burned in 200 percent theoretical air. For complete combustion, how many kmol of water must be sprayed into the combustion chamber per kmol of fuel if the products of combustion are to have a dew-point temperature of $60^{\circ} \mathrm{C}$ when the product pressure is 100 kPa?

Butane gas and 200% theoretical air, both at 25$^{\circ} \mathrm{C}$, enter a steady-flow combustor. The products of combustion exit at 1000 K. Calculate the heat transfer from the combustor per kmol of butane burned.

Methyl alcohol $\left(\mathrm{CH}_{3} \mathrm{OH}\right)$ is burned with 50 percent excess air. The combustion is incomplete with 10 percent of the carbon in the fuel forming carbon monoxide. Calculate the mole fraction of carbon monoxide and the apparent molecular weight of the products.