Identify the correct statement for the change of Gibbs energy for a system (ΔG_system) at constant temperature and pressure

• If ΔG_system > 0, the process is spontaneous

• If ΔG_system =0, the system has attained equilibrium

• If ΔG_system < 0, the system is still moving in a particular direction
  

• If ΔG_system < 0, the system is still moving in a particular direction
  

Assume each reaction is carried out in an open container. For which reaction will ΔH = ΔE?

• H₂ (g) + Br₂ (g) →2HBr (g)

• C (s) + 2 H₂O (g) → 2 H₂ (g) + CO₂ (g)

• PCl₅ (g) →PCl₃ (g) + Cl₂ (g) 

• PCl₅ (g) →PCl₃ (g) + Cl₂ (g) 

Given: The mass of electron is 9.11 x 10^-31 kg
Planck constant is 6.626 x 10^-34 Js,
the uncertainty involved in the measurement of velocity within a distance of 0.1 A is:

• 5.79 x 10⁶ ms^-1

• 5.79 x 10⁷ ms^-1

• 5.79 x 10⁸ ms^-1

• 5.79 x 10⁸ ms^-1

4.

The enthalpy and entropy change for the reaction:

Br₂ (l) + Cl₂ (g)→ 2BrCl (g)

are 30 kJ mol^-1 and 105 JK^-1 mol^-1 respectively. The temperature at which the reaction will be in equilibrium is:

• 285.7 K 

• 273 K

• 450 K

• 450 K

For the reaction,

CH₄  (g) + 2 O₂ (g) ⇌ CO₂ (g) + 2H₂O (l), 

Δ_rH = - 170. 8 kJ mol^-1

Which of the following statements is not true? 

• At equilibrium, the concentrations of CO₂ (g) and H₂O (l) are not equal

• The equilibrium constant for the reaction is given by K_p = 

• Addition of CH₄ (g) or O₂ (g) at equilibrium will cause a shift to the right

• Addition of CH₄ (g) or O₂ (g) at equilibrium will cause a shift to the right

The enthalpy of combustion of H₂, cyclohexene (C₆H₁₀) and cyclohexene (C₆H₁₂) are -241, -3800 and -3920 kJ per mol respectively.The heat of hydrogenation of cyclohexane is:

• -212 kJ mol

• +121 kJ mol

• +242 kJ per mol

• +242 kJ per mol

Which of the following pairs consitutes a buffer?

• HNO₂ and NaNO₂

• NaOH and NaCl

• HNO₃ and NH₄NO₃

• HNO₃ and NH₄NO₃

The hydrogen ion concentration of a 10^-8 M HCL aqueous solution at 298 K (K_w = 10^-14) is:

• 1.0 x 10^-6

• 1.0525 x 10^-7 M

• 9.525 x 10^-8 M

• 9.525 x 10^-8 M

In which of the following molecules are all the bonds not equal? 

• ClF₃

• BF₃

• AlF₃

• AlF₃

The orientation of an atomic orbital is governed by:

• azimuthal quantum number

• spin quantum number

• magnetic quantum number

• magnetic quantum number