Unit 4-5 MCQ

Front

What is the most likely sequence and orientation of collisions of reactants in a chemical reaction?

Back

The sequence and orientation of collisions must allow for effective overlap of electron clouds, leading to the formation of products. This is often described by collision theory.

Front

What is the oxidation state of nitrogen in NO, NO2, NO3-1, and NO2-1?

Back

The oxidation states of nitrogen are: NO (oxidation state +2), NO2 (oxidation state +4), NO3-1 (oxidation state +5), NO2-1 (oxidation state +3). The greatest oxidation state is in NO3-1.

Front

What ions remain in solution after a reaction has gone to completion?

Back

The ions that remain in solution are those that do not participate in the reaction, often referred to as spectator ions.

Front

What are the units of the rate constant (k) for a second-order reaction?

Back

The units of the rate constant k for a second-order reaction are L mol-1 time-1.

Front

What does an energy profile for a reaction indicate?

Back

An energy profile shows the energy changes during a reaction, including activation energy and the energy of reactants and products.

Front

What is collision theory in chemistry?

Back

Collision theory states that for a reaction to occur, reactant particles must collide with sufficient energy and proper orientation.

Front

Define the term 'activation energy'.

Back

Activation energy is the minimum energy required for a chemical reaction to occur.

Front

What is a catalyst and how does it affect a chemical reaction?

Back

A catalyst is a substance that increases the rate of a chemical reaction without being consumed, by lowering the activation energy.

Front

Explain the concept of equilibrium in a chemical reaction.

Back

Equilibrium is the state in which the rates of the forward and reverse reactions are equal, resulting in constant concentrations of reactants and products.

Front

What is the difference between endothermic and exothermic reactions?

Back

Endothermic reactions absorb heat from the surroundings, while exothermic reactions release heat.