January 2025 Multiple Choice

Front

What is thermal energy transfer?

Back

Thermal energy transfer is the process of heat moving from a hotter object to a cooler one until thermal equilibrium is reached.

Front

What happens when a hot object is placed in a cooler environment?

Back

Thermal energy is transferred from the hot object to the cooler environment.

Front

What is a redox reaction?

Back

A redox reaction is a chemical reaction that involves the transfer of electrons between two species, resulting in changes in oxidation states.

Front

What is the significance of collision energy in chemical reactions?

Back

Chemical reactions are more likely to occur when reactant particles collide with sufficient energy to overcome the activation energy barrier.

Front

What distinguishes O₂ from O₃ in terms of molecular structure?

Back

O₂ (oxygen) has a diatomic molecular structure, while O₃ (ozone) has a triatomic molecular structure.

Front

How do the properties of O₂ and O₃ differ?

Back

O₂ is a colorless, odorless gas essential for respiration, while O₃ is a pale blue gas with a distinct smell, used in the stratosphere to block UV radiation.

Front

What is a mixture in chemistry?

Back

A mixture is a combination of two or more substances that retain their individual properties and can be separated by physical means.

Front

What is the role of energy in chemical reactions?

Back

Energy is required to break bonds in reactants and form new bonds in products during a chemical reaction.

Front

What is the importance of proper orientation in particle collisions?

Back

Proper orientation ensures that the reactive parts of the molecules align correctly, increasing the likelihood of a successful reaction.

Front

What is the difference between a chemical change and a physical change?

Back

A chemical change results in the formation of new substances, while a physical change alters the form of a substance without changing its chemical identity.