Equilibrium Constant Calculations

A vessel was filled with NOCl gas until the concentration was 0.398 mol/liter. The temperature of the system was increased to 245 oC and the system was allowed to undergo the reaction, 2NOCl(g) --> 2NO(g) + Cl2(g), until equilibrium was attained. The physical chemistry students did a calculation and found the [Cl2] at that point was 0.0225 mol/liter. Calculate the value of Kc at that temperature.

• 2.87 x 10-3

• 3.66 x 10-4

• 8.13 x 10-3

• 1.29 x 10-4

• 9.14 x 10-5

Sampel SO3 dimasukan ke dalam reaktor kosong dan vakum, kemudian dipanaskan hingga 600 K. Kesetimbangan berikut terjadi: 2 SO3(g) --> 2SO2(g) + O2(g). Jika tekanan total sistem adalah 3.0 atm dan fraksi mol O2 adalah 0.12, tentukan nilai Kp ….

• 0.15

• 0.05

• 2.5 x 10-2

• 1 x 10-4

• 3.5 x 10-5

Perhatikan reaksi dan tetapan kesetimbangannya: N2O4(g) --> 2NO2(g)Kc=5.85×10−3 suatu campuran reaksi mengandung [NO2]=0.0255M dan [N2O4]=0.0331M. Tentukan Qc dan ke arah mana reaksi berlangsung.

• Pembentukan NO2

• Penguraian N2O4

• Ke arah pereaks

• Tidak berubah

• Ke arah produk

Untuk perubahan fasa Br2(ℓ) --> 2Br2(g), ΔH∘=+31.0 kJ.mol−1 dan ΔS∘=92.9 J.mol−1.K−1. Dengan asumsi ΔH dan ΔS hampir tidak bergantung pada temperatur, tentukan temperatur dimana terjadi kesetimbangan antara Br2(ℓ) dan Br2(g) pada 1 atm (titik didih normal Br2)

• 273 K

• 298 K

• 334 K

• 375 K

• 450 K

A study of the system, H2(g) + I2(g) --> 2HI(g), was carried out. Kc = 54.9 at 699.0K for this reaction. A system was charged with 2.50 moles of H2(g) and 2.50 moles I2(g) in a 5.00 liter vessel as the only components initially. The system was brought up to 699.0 K and allowed to attain equilibrium. How many moles of H2(g) should there be in the container at that time?

• 0.531 moles

• 0.674 moles

• 0.594 moles

• 1.00 moles

• 0.266 moles

The thermochemical equation representing one process used for the synthesis of ammonia involves the equilibrium shown, N2(g) + 3 H2(g) --> 2 NH3(g) For this reaction, H° = 92.2 kJ, G° = 33.4 kJ. All things considered, one concludes that

• the coefficients give us the mole ratios but not the volume ratios of the reacting species.

• an increase in pressure favors an increase in the yield of ammonia.

• carrying out the reaction at a higher temperature shifts the position of equilibrium to the right, thus favoring an increase in the yield of ammonia.

• cooling the mixture to remove ammonia from the reaction mixture unfortunately also decreases the overall yield of ammonia.

• the mixture does not need heating, in fact, cooling the mixture assists the rapid establishment of equilibrium.

Determine the equilibrium constant Kp at 25°C for the reaction: N2(g) + 3H2(g) --> 2NH3(g) (G°f (NH3(g)) = -16.6 kJ/mol)

• 1.52 x 10-6

• 2.60

• 8.28 x 10-2

• 13.4

• 6.60 x 10^5

Perhatikan reaksi berikut yang terjadi pada suhu 25 oC: 2NO(g) + O2(g) --> 2NO2(g) Jika G°rxn adalah -69.7 kJ/mol. Jika ke dalam wadah tertutup dimasukkan sejumlah gas NO2 hingga tekanan wadah menjadi 5 atm, lalu dibiarkan hingga terjadi kesetimbangan pada suhu 25 oC, tentukan tekanan parsial O2 saat terjadi kesetimbangan ….

• 2.5 atm

• 1 atm

• 0.5 atm

• 0.1 atm

• hamper tidak terbentuk

The equilibrium constant at 427°C for the reaction N2(g) + 3H2(g) ⇆ 2NH3(g) is Kp = 9.4 x 10-5. Calculate the value of G° for the reaction at this temperature.

• 56 kJ/mol

• -56 kJ/mol

• -33 kJ/mol

• 33 kJ/mol

• 1.3 J/mol

Nitrogen monoxide reacts with bromine at elevated temperatures according to the equation 2NO(g) + Br2(g) --> 2NOBr(g) In a certain reaction mixture the rate of formation of NOBr(g) was found to be 4.50 x 104 mol L1 s1. What is the rate of consumption of Br2(g)?

• 4.50 x 104 mol L1 s1

• 2.25 x 104 mol L1 s1

• 9.00 x 104 mol L1 s1

• 2.12 x 104 mol L1 s1

• 2.03 x 103 mol L1 s1