# Answer: Nitromethane, CH3NO2, can be used as a fuel. When

Chapter 9, Problem 9.97

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QUESTION:

Nitromethane, CH3NO2, can be used as a fuel. When the liquid is burned, the (unbalanced) reaction is mainly CH3NO2 1l2 1 O2 1g2 h CO2 1g2 1 N2 1g2 1 H2O1g2 a. The standard enthalpy change of reaction (DH8rxn) for the balanced reaction (with lowest wholenumber coefficients) is 21288.5 kJ. Calculate DHf 8 for nitromethane. b. A 15.0-L flask containing a sample of nitromethane is filled with O2 and the flask is heated to 100.C.At this temperature, and after the reaction is complete, the total pressure of all the gases inside the flask is 950. torr. If the mole fraction of nitrogen (xnitrogen) is 0.134 after the reaction is complete, what mass of nitrogen was produced?

QUESTION:

Nitromethane, CH3NO2, can be used as a fuel. When the liquid is burned, the (unbalanced) reaction is mainly CH3NO2 1l2 1 O2 1g2 h CO2 1g2 1 N2 1g2 1 H2O1g2 a. The standard enthalpy change of reaction (DH8rxn) for the balanced reaction (with lowest wholenumber coefficients) is 21288.5 kJ. Calculate DHf 8 for nitromethane. b. A 15.0-L flask containing a sample of nitromethane is filled with O2 and the flask is heated to 100.C.At this temperature, and after the reaction is complete, the total pressure of all the gases inside the flask is 950. torr. If the mole fraction of nitrogen (xnitrogen) is 0.134 after the reaction is complete, what mass of nitrogen was produced?

Problem 9.97

Nitromethane, CH3NO2, can be used as a fuel. When the liquid is burned, the (unbalanced) reaction is mainly

a). The standard enthalpy change of reaction (DH8rxn) for the balanced reaction (with lowest whole number coefficients) is -1288.5 kJ. Calculate for nitromethane. b. A 15.0-L flask containing a sample of nitromethane is filled with O2 and the flask is heated to 100.C.At this temperature, and after the reaction is complete, the total pressure of all the gases inside the flask is 950. torr. If the mole fraction of nitrogen (x nitrogen) is 0.134 after the reaction is complete, what mass of nitrogen was produced?

Step by Step Solution

Step 1 of 2

The standard enthalpy change of reaction is defined as the change in enthalpies when one

mole of compound is reacted under the standard conditions.

It is represented as follows:

= The enthalpy of reaction

=  enthalpy of formation

and   = stoichiometric coefficient for reactant and products respectively.

a)

The balanced reaction is the reaction in which the atoms of each element on the right hand side is equal to the left hand side.

The balanced equation is as follows:

The standard enthalpy of reaction is -1288.5 kJ.

From the appendix 4,

The values of enthalpy of formation of  and  is zero,  is -393.5 kJ / mol and  is -242 kJ / mol.

Thus, the enthalpy of formation of products is calculated as follows:

The enthalpy of formation of reactants is calculated as follows:

Now the enthalpy of formation of nitromethane can be determined as follows:

Therefore, the enthalpy of formation of nitromethane is -434.3 kJ / mol.

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