3sec - quiz 12

In the reaction:

AgCl_(s) ⇋Ag⁺_(aq.)+Cl^-_(aq.)

By adding HCl solution , reaction will be shifted:

• right & Ag⁺ increase

• right & Ag⁺ decrease

• left & Ag⁺ increase

• left & Ag⁺ decrease

Which one of the following reactions its rate of decomposition increase by increasing the temperature.

• SO3(g) ⇌ SO2(g) + ½ O2(g)

  ∆H= (+154Kj/mol)

• N₂H_4(g) ⇌ N_2(g)+2H_2(g)

  ∆H=(-494Kj/mol)

• 2HCl_(g) ⇌ H_{2(g) +}Cl_2(g)

  ∆H= (-134Kj/mol)

• NO_(g) ⇌ ½N_2(g) + ½O_2(g)

  ∆H= (-234Kj/mol)

The following system is in equilibrium:

2S_(s) + 5F_{2 (g)} ⇌ SF_{4 (g)} + SF_{6 (g)}

The equilibrium will shift to the right if ………….

• the pressure on the system is decreased

• the concentration of SF₆ is increased

• the concentration of SF₄ is increased

• the pressure on the system is increased

For the reaction : A + B = C , when the concentration of reactants = concentration of products , this means:

• this reaction sure reach to equilibrium state

• this reaction sure doesn’t reach to equilibrium state

• this reaction may reach to equilibrium state or not

• this reaction sure is a complete reaction

The following figure represents the progression of a chemical reaction:

Which of the following statements represents correctly this reaction?

• This reaction is a reversible reaction

• Case (3) represents an equilibrium state

• Case (4) represents the state when the forward reaction rate equals the backward reaction rate

• The case (1) and (5) indicate that this reaction is complete

If the rate of formation of ammonia gas by (Haber - Bosch) method equals 2.5 x 10^-4 mol L^-1 s^-1,then the rate of consumption of nitrogen gas during the process equals ……… mol L^-1 s^-1

• -1.25 x 10^-4

• -3.75 x 10^-4

• -5 x 10^-4

• -2.5 x 10^-4

when dissolving a solid matter by heating to give gaseous products, so contraction of the volume of container of the reaction leads to………...

• reaction goes forward

• reaction would not be affected

• reaction goes backward

• no correct answer

All the following increase the rate of the chemical reaction except …

• Using a catalyst

• Increasing the reactants concentrations

• Raising the temperature

• Increase the activation energy

Methane gas combusts slowly in the atmospheric air at the room temperature, but when a piece of platinum is added to the vessel of the reaction which contains a mixture of methane and air, methane combusts instantaneously. What is the role of platinum in this reaction?

• Decreasing the rate of the reaction

• Releasing the stored energy in the reactants

• Increasing the value of ∆H of the reaction

• Reducing the activation energy of the reaction

If the activation energy of reaction A= 120 KJ/mol, activation energy of reaction B= 270 KJ/mol the rate of reaction ……...

• A more than B

• B more than A

• A equal B

• B little more than A