SABIS Grade 11 Term 1 Week 7 Lesson 13

Multiple Choice

Le Chatelier's Principle states that if an equilibrium system is subjected to a change processes will

occur to

• fully counteract the imposed change.

• partially counteract the imposed change.

• go with the imposed change.

Multiple Choice

For the reaction...
SO_2(g) + O_2(g) <−>  SO_3(g)
If the concentration of SO_2(g)  is increased, the equilibrium of the reaction will ___________.

• shift to the left
• shift to the right
• not shift

Multiple Choice

For the reaction...
energy +  N_2(g)  +  O_2(g)  <−>  2NO_(g)
If  O_2(g) is removed, the  concentration of N₂ will _______.

• increase
• decrease
• remain the same
• double

Multiple Choice

A_(g) + B_(aq) <> C_(s)

ΔH= -453 kJ/mol

If the [B] is decreased then the reaction is will shift to the _______.

• Left

• Right

• Stays the same

• Up

Multiple Choice

Which is NOT a way to stress a closed chemical system at equilibrium?

• change temperature

• add a reactant

• take away a chemical in the reaction

• add a catalyst

Multiple Choice

Increasing the pressure on an equilibrium system will

• shift the reaction to the side with more moles of chemicals

• shift the reaction to the side with more moles of gas

• shift the reaction to the side with fewer moles of gas

• shift the reaction to the side with fewer moles of chemicals

Multiple Choice

Increasing the temperature of a closed equilibrium system

• will shift the reaction in the endothermic direction

• will shift the reaction in the exothermic direction

• will not shift the reaction

• will shift the reaction to the side with heat

Multiple Choice

For the following equilibrium reaction:

N₂ (g) + 3 H₂ (g) <==> 2 NH₃ (g) ΔH=-386 kJ/mol

Predict the direction that the reaction will proceed, or shift, if...

The volume of the container is decreased.

• right

• left

• no effect

Multiple Choice

H₂O⇌H⁺+OH^-

This reaction is

• Exothermic

• Enodthermic

H₂O⇌[H⁺][OH^-]

​

This reaction is endothermic

means forward is endothermic

​

Forward temperature Decrease​

Multiple Choice

H2O⇌H⁺+OH^-

^{This reaction is endothermic}

If the system is heated (temperature increases) the system will try to

decrease the temperature so it moves in

• Forward direction

• Backward direction

Multiple Choice

H2O⇌H⁺+OH^-

^{This reaction is endothermic}

^{If the system is heated (temperature increases) the system will try to decrease the temperature so it moves in}

^{Forward direction this causes products concentration to}

• increase

• decrease

Multiple Choice

H2O⇌H⁺+OH^-

^{This reaction is endothermic}

^{If the system is heated (temperature increases) the system will try to decrease the temperature so it moves in}

^{Forward direction this causes products concentration to increase}

^causing

kw=[H⁺][OH^-] to

• increase

• decrease

Dissociation of water is endothermic:

H₂O ⇌ H⁺+OH^-

As temperature increases, the concentrations of ions increases so Kw increases

K-chemistry.com

kw=[H⁺][OH^-]

Multiple Choice

In aqueous solutions

Kw = [H⁺][OH^–]

• at all times

• Sometimes

• in acidic solutions

• in basic solutions

Multiple Select

An electrolyte is a substance

• that contains metal.

• that produces electricity.

• whose aqueous solution conducts an electric current.

• which dissolves in water to give positive and negative ions.

• that is made up of ions in the pure state.

Multiple Select

A strong electrolyte is a substance

• that contains metal.

• which dissolves in water and exclusively gives positive and negative ions.

• which dissolves in water to give positive and negative ions.

• that is made up of ions in the pure state

• whose particles in water dissociate only partially into ions.

Multiple Select

A Weak electrolyte is a substance

• that contains metal.

• which dissolves in water and exclusively gives positive and negative ions.

• which dissolves in water to give positive and negative ions.

• that is made up of ions in the pure state

• whose particles in water dissociate only partially into ions.

Multiple Select

• equilibrium will be reached more rapidly but Kw remains constant

• Kw would decrease with increasing temperature.

• With increasing temperature the equilibrium will shift to the right, increasing the

  concentrations of [H+] and [OH–], so increasing the value of Kw.

• With increasing temperature the equilibrium will shift to the left, decreasing the concentrations of

  [H+] and [OH–], so decreasing the value of Kw.

Multiple Select

Which ions are present in all aqueous solutions?

• H+

• OH–

• NO3

• Na+

• Fe+2

Multiple Select

An electrolyte is a substance

• that contains metal.

• that produces electricity.

• whose aqueous solution conducts an electric current.

• which dissolves in water to give positive and negative ions.

• that is made up of ions in the pure state.

Multiple Choice

H2O⇌H⁺+OH^-

^{This reaction is}

• Exothermic

• Enodthermic

Multiple Select

Which of the following is true about water at 25 degrees C if either

H⁺(aq) or OH^–(aq)

are added to it?

• [OH–] = [H+] =

  1.00× 10–7 M

• [OH–] ≠ [H+] ≠

  1.00× 10–7 M

• [OH–] ×[H+] =

  1.00 × 10–14 M

Multiple Select

Which of the following is true about an aqueous solution where

[H+] = 1.00 × 10^–10 M?

• [OH–] = [H+]

  = 1.00 × 10^–7 M.

• [OH–] = [H+]

  = 1.00 × 10^–10 M

• [OH–] = [H+]

  = 1.00 × 10^–14 M

• [H+] =

  1.00 × 10^–4 M

• [OH–] =

  1.00 × 10^–4 M

Multiple Select

An operational definition is

• a definition of an operation.

• a definition based on set of actions that can be performed in the lab.

• a definition based on a theoretical concept.

• a definition based on a single property.

• a definition that satisfies a number of mathematical conditions.

Multiple Select

Which of the following is an example of (or contains) an acid?

• Vinegar.

• Ammonia solution.

• Yoghurt.

• Na2CO3.

• NaOH.

Multiple Select

Which of the following is (or is a part of) the operational definition of an acid?

• It contains oxygen.

• Its aqueous solution conducts an electric current.

• If its aqueous solution is added to zinc metal, hydrogen gas is liberated.

• If blue litmus paper is dipped in its aqueous solution, it turns to red.

• It contains hydrogen.

Multiple Select

Which of the following is a property of HCl _(aq) solutions?

• It contains oxygen.

• Its aqueous solution conducts an electric current.

• If its aqueous solution is added to zinc metal, hydrogen gas is liberated.

• If blue litmus paper is dipped in its aqueous solution, it turns to red.

• It contains hydrogen.

Multiple Select

A conceptual definition is

• a definition of a concept.

• a definition that satisfies a number of mathematical conditions.

• a definition based on set of actions that can be performed in the lab.

• a definition based on a theoretical concept.

• a definition based on a single property.

Multiple Choice

Which of the following is a titration ?

• A state of equilibrium for acid-base systems.

• Mixing acid and base solutions containing the same number of moles.

• The progressive addition of a base to an acid or vice versa.

• The addition of a fixed volume of base to an acid with an indicator.

• The addition of a fixed volume of acid to a base with an indicator.

Multiple Select

Which of the following is (or is a part of) the conceptual definition of an acid?

• It contains hydrogen.

• It can increase the [OH–(aq)] in aqueous solution.

• Its aqueous solution conducts an electric current.

• If its aqueous solution is added to zinc metal, hydrogen gas is liberated.

• It can increase the [H+_(aq)] in aqueous solution.

Multiple Select

Which of the following is an example of (or contains) a base?

• Vinegar.

• Ammonia solution.

• Yoghurt.

• NaOH.

• H2SO4

Multiple Select

Which of the following is (or is a part of) the operational definition of a base?

• If its aqueous solution is added to zinc metal, hydrogen gas is liberated.

• If blue litmus paper is dipped in its aqueous solution, it turns to red.

• If red litmus paper is dipped in its aqueous solution, it turns to blue.

• It tastes sour and bitter at the same time.

• It feels slippery, like soap.

Multiple Select

Which of the following is (or is a part of) the conceptual definition of a base?

• It contains hydrogen.

• It contains oxygen.

• It can increase the [OH–(aq)] in aqueous solution.

• d) Its aqueous solution conducts an electric current.

• It can decrease the [H+(aq)] in aqueous solution.

Multiple Select

An acid-base indicator is

• an instrument to mix exactly equal amounts of acid and base solutions containing the same number of moles.

• a dye whose colour is sensitive to the change of [H+].

• a meter to measure the amount of acid and base added.

• a colormeter used for the addition of a fixed volume of acid to a base.

• an instrument to determine the state of equilibrium for acid-base systems.

Multiple Select

Litmus, a dye, is

• blue in an acidic solution and red in a basic solution.

• orange in an acidic solution and red in a basic solution.

• red in an acidic solution and blue in a basic solution.

• pink in an acidic solution and colourless in a basic solution.

• colourless in an acidic solution and pink in a basic solution.

Multiple Select

Phenolphthalein is coloured

• blue in acid and red in base.

• red in acid and blue in base.

• colourless in acid and pink in base.

• pink in acid and colourless in base.

• red in acid and yellow in base.

Multiple Select

In titrations using phenolphthalein, what is the solution placed in the burette?

• The acid.

• The base.

• Either the base or the acid may be used.

• Phenolphthalein.

• A mixture of the two solutions.

Multiple Select

In titrations, the volume of base used is determined by

• Taking the last reading of the burette.

• Taking the first reading of the burette.

• Taking the difference between the last and first reading of the pipette.

• Taking the first reading of the pipette.

• Taking the difference between the last and first reading of the burette.

Multiple Select

You realize that the end-point of an acid-base titration with phenolphthalein has been reached when

• the addition of a single drop turns the liquid in the flask pink.

• all the base finishes.

• the addition of a single drop turns the liquid in the burette pink.

• the addition of a single drop turns the liquid in the flask colourless.

• you see the solution become neutral.