Which of the following changes is an irreversible change?

• Melting of ice cube

• Heating hydrated CuSO₄

• Frying an egg

• Thermal decomposing NH₄Cl

What type of reactions can able to change products back to the their original form?

• Reversible reactions

• Irreversible reactions

• Combustion reactions

• Combination reactions

Which of the following combinations is correct?

• reversible ⇌

  irreversible →

• reversible ←

  irreversible →

• reversible ⇌

  irreversible ←

• irreversible ⇌

  reversible →

In an exothermic reaction, heat is ...

• taken in
• given out

If a reversible reaction is exothermic in the forward direction, it will be ...

• exothermic in the reverse direction

• endothermic in the forward direction too

• endothermic in the reverse direction

• not involve energy in reverse direction

This picture shows the hydration of copper sulfate.

Which substance is the ANHYDROUS version?

• the blue solid

• the white solid

When heating the hydrated copper sulfate, is the reaction endothermic or exothermic?

• Endothermic

• Exothermic

Dynamic equilibrium is reached when...

• Mass of reactants

  =

  Mass of products

• Rate of forward reaction

  =

  Rate of reverse reaction

• Speed of reactants

  =

  Speed of products

• Number of reactants

  =

  Number of products

When dynamic equilibrium is achieved, this means that...

• The concentration of the reactants and products will not change

• The reaction will have finished

• The rate of reaction will be the fastest

• The reactants and products will have been fully used up

Dynamic equilibrium can only happen...

• For IRREVERSIBLE reactions in an OPEN system

• For IRREVERSIBLE reactions in a CLOSED system

• For REVERSIBLE reactions in an OPEN system

• For REVERSIBLE reactions in a CLOSED system