While ethanol (CHCH2OH is produced naturally by fermentation, e.g. in beer- and

Question

While ethanol (CHCH2OH is produced naturally by fermentation, e.g. in beer- and wine-making, industrially it is synthesized by reacting ethylene CH2CH2) with water vapor at elevated temperatures. A chemical engineer studying this reaction fills a 500. mL flask at 20. °C with 0.70 atm of ethylene gas and 4.5 atm of water vapor. He then raises the temperature considerably, and when the mixture has come to equilibrium determines that it contains 0.38 atm of ethylene gas and 4.18 atm of water vapor. The engineer then adds another 0.23 atm of ethylene, and allows the mixture to come to equilibrium again. Calculate the pressure of ethanol after equilibrium is reached the second time. Round your answer to 2 significant digits. atm x10

Explanation / Answer

Balanced chemical reaction with ICE TABLE

C2H4(g) + H2O(g) <===> CH3CH2OH(g)

I 0.70 4.5

C - x - x +x

E 0.70-x 4.5-x x

After equilibrium

P(C2H4) = 0.38 atm

0.70 - x = 0.38

x = 0.32 atm

P(H2O) = 4.18 atm

4.5 - x = 4.18

x = 0.32 atm

P(CH3CH2OH) = 0.32 atm

Equilibrium constant expression of the reaction

Kp = 0.32 / (4.18)*(0.38)

= 0.2015

Now add 0.23 arm of C2H4

New pressure = 0.23+0.70 = 0.93 atm

Balanced chemical reaction with ICE TABLE

C2H4(g) + H2O(g) <===> CH3CH2OH(g)

I 0.93 4.5

C - x - x +x

E 0.93-x 4.5-x x

Equilibrium constant expression of the reaction

Kp = x / (4.5-x)*(0.93-x)

0.2015 * (4.5-x)*(0.93-x) = x

(0.90675 - 0.2015 x) * (0.93-x) = x

0.8432775 - 0.90675 x - 0.187395 x + 0.2015 x2 - x = 0

0.2015 x2 - 2.094145 x + 0.8432775 = 0

x = 0.4196

After second equilibrium

P(CH3CH2OH) = 0.4196 = 4.196*10^-1 atm

Related Questions

Navigate

• Browse (All)
• Browse W
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.