Unit 2 Chemistry Review 2024-2025

Front

What is the half-life of a radioactive substance?

Back

The half-life is the time required for half of the radioactive atoms in a sample to decay.

Front

How do you calculate the remaining amount of a substance after a certain number of half-lives?

Back

Remaining amount = Initial amount × (1/2)^(number of half-lives).

Front

What is the chemical name for SF6?

Back

Sulfur hexafluoride.

Front

What type of reaction occurs when a hydrocarbon reacts with oxygen?

Back

Combustion reaction.

Front

Define a reactant in a chemical reaction.

Back

A reactant is a substance that is consumed during a chemical reaction.

Front

What do subscripts in a chemical formula represent?

Back

Subscripts indicate the number of atoms of each element in a molecule.

Front

What is the general form of a combustion reaction?

Back

Hydrocarbon + O2 → CO2 + H2O.

Front

What is the difference between a coefficient and a subscript in a chemical equation?

Back

Coefficients indicate the number of molecules, while subscripts indicate the number of atoms in each molecule.

Front

What is the significance of balancing a chemical equation?

Back

Balancing ensures that the law of conservation of mass is obeyed, meaning the number of atoms of each element is the same on both sides.

Front

What is the product of a combustion reaction?

Back

The products are carbon dioxide (CO2) and water (H2O).