Chemical Reactions Unit Assessment- MC

In terms of entropy and energy, systems in nature tend to undergo changes toward

• lower entropy and lower energy

• lower entropy and higher energy

• higher entropy and lower energy

• higher entropy and higher energy

Entropy is a measure of the

• acidity of a sample

• disorder of a system

• concentration of a solution

• chemical activity of an element

Which statement describes a chemical reaction at equilibrium?

• The rate of the forward reaction is equal to the rate of the reverse reaction.

• The concentration of reactants is equal to the concentration of products.

• The mass of the reactants is equal to the mass of the products.

• The rate of the forward reaction is slowing down while the rate of the reverse reaction is speeding up.

According to Table I, a 1.0-mole sample of which compound absorbs the greatest amount of heat as it dissolves in water?

• LiBr

• NaOH

• NaCl

• NH₄Cl

An effective collision between reactant particles requires the particles to have the proper

• energy and orientation

• charge and orientation

• energy and mass

• charge and mass

Given the reversible chemical reaction: 2NO₂(g) ⇄ N₂O₄(g) + 58 kJ, which change will increase the concentration of NO₂?

• Increase temperature

• Remove N₂O₄

• Increase pressure

• Add a catalyst

What statement about activation energy for a reversible reaction is correct?

• Activation energy is the same sign but different value for the forward and reverse reactions.

• Activation energy is the same sign and same value for the forward and reverse reactions.

• Activation energy is a different sign and different value for the forward and reverse reactions.

• Activation energy is a different sign but the same value for the forward and reverse reactions.

According to Table J, which metal is most likely to be found as a pure element instead of as part of a compound?

• Copper

• Sodium

• Titanium

• Iron

Given the potential energy diagram for a chemical reaction, which numbered interval represents the heat of reaction?

• 1

• 2

• 3

• 4

Which type of equilibrium exists in a sealed flask containing Br₂(ℓ) and Br₂(g) at 298 K and 1.0 atm?

• Chemical Equilibrium

• Solution Equilibrium

• Phase Equilibrium

• No equilibrium can exist in the sealed flask.