Q.1
What is the symbol which is used in reversible reactions?
  • →
  • Δ
  • +
  • ⇌
Q.2
What are the names of the ways a liquid changes to a gas
  • Evaporation
  • Boiling
  • Condensation
  • Both A & B
Q.3
Which of the following is a sign that a chemical reaction has occurred?
  • change in shape
  • melting
  • formation of a gas
  • dissolving
Q.4
To put out a fire, we need to
  • Remove one of the elements of the fire triangle.
  • Call the ambulance.
  • Run away.
  • All of above
Q.5
Water can't be used on
  • Wood.
  • Paper.
  • Flammable liquids, like oil.
  • All of above
Q.6
Fuels are _____ that are very good at burning.
  • Substances
  • Cars
Q.7
Irreversible changes can also be called
  • Physical changes
  • Chemical changes
Q.8
Reversible changes are also called
  • Physical changes
  • Chemical changes
Q.9
A ______ change can be undone and generally refers to a change of state.
  • Reversible
  • Irreversible
Q.10
What is a closed system
  • It gives out energy
  • The reactants and the products do not escape from reaction mixture
  • It takes in energy
  • The reactants and the products escape from he reaction mixture to be kept in the system
Q.11
What is a Reversible reaction
  • A reaction going forward and backward at same time
  • A reaction going forward and backward at different time
  • forward reaction
  • backward reaction
Q.12
Why is a reaction described as irreversible?
  • The products cannot be turned directly back into the reactants.
  • You need to apply heat to make the reaction work.
  • The products can be turned back into the reactants.
  • The reactants cannot be turned into the products.
Q.13
Which of the following changes is irreversible change?
  • Melting of ice cube
  • Heating hydrated CuSO4
  • Frying an egg
  • Thermal decomposing NH4Cl
Q.14
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
Q.15
Which of the following reactions is irreversible?
  • Thermal decomposition of ammonium chloride.
  • Heating hydrated copper sulfate.
  • Composition of ammonia gas from nitrogen and hydrogen gases.
  • Combustion of ethanol.
Q.16
Which of the following reactions never goes completion in a closed container?
  • H2 + I2 ⇌ 2HI
  • C2H5OH + 3O2 → 2CO2 + 3H2O
  • NaOH + HCl → NaCl + H2O
  • CuSO4 + Zn → ZnSO4 + Cu
Q.17
When amounts of reactants and products become constant in reversible reaction, what might happen to the reversible reaction?
  • Reversible reaction reaches equilibrium.
  • Reversible reaction fastens forward reaction.
  • Reversible reaction fastens reverse reaction.
  • Reversible reaction slows down forward reaction.
Q.18
Which of the following chemical reactions is reversible?
  • CH4 + O2 ⇌ CO2 + H2O
  • CuSO4.5H2O → CuSO4 + 5H2O
  • NH4Cl ⇌ NH3 + HCl
  • CaCO3 → CaO +CO2
Q.19
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
Q.20
Which of the following combination is correct?
  • reversible ⇌irreversible →
  • reversible ←irreversible →
  • reversible ⇌irreversible ←
  • irreversible ⇌reversible →
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