Question

A sample of C2H4 with a pressure of 1.63 atm and a volume of 234 mL is allowed to react with excess H2 at 117 °C. H2 (g) + C2H4 (g) C2H6 (g) Calculate the pressure of the C2H6 produced in the reaction if it is transferred to a 1.20-L flask and cooled to 35 °C.

Answer 1

To find the pressure of C2H6 produced in the reaction, use the stoichiometry of the balanced chemical equation and the ideal gas law. Calculate the number of moles of C2H6 produced and then use the ideal gas law equation with the new volume and temperature to find the pressure of C2H6 in the new flask.

Step-by-step explanation:

To calculate the pressure of C2H6 produced in the reaction, we can use the stoichiometry of the balanced chemical equation and the ideal gas law.

First, we need to calculate the number of moles of C2H6 produced.

From the equation, we can see that 1 mole of C2H4 produces 1 mole of C2H6. Since the reaction has excess H2, the moles of C2H4 remain constant.

To find the new pressure, we can use the ideal gas law equation: PV = nRT, where P is the pressure, V is the volume, n is the number of moles, R is the ideal gas constant, and T is the temperature.

Before using the ideal gas law, we need to convert the temperature to Kelvin: 117 °C + 273 = 390 K.

We also need to convert the volume to liters to match the units of the ideal gas constant: 234 mL = 0.234 L.

Now we can substitute the known values into the ideal gas law equation:

(1.63 atm)(0.234 L) = n(0.0821 L·atm/mol·K)(390 K). Solving for n, we find that the number of moles of C2H6 produced is 0.0160 mol.

Finally, we can calculate the pressure of C2H6 in the new flask using the same ideal gas law equation, but with the new volume and temperature:

(P)(1.20 L) = (0.0160 mol)(0.0821 L·atm/mol·K)(308 K).

Solving for P, we find that the pressure of C2H6 in the new flask is 0.120 atm.