AP Chemistry Lab-Based FRQ Practice

Front

What is mass percent and how is it calculated?

Back

Mass percent is the mass of a solute divided by the total mass of the solution, multiplied by 100. It is used to express the concentration of a component in a mixture.

Front

How does the volume of solvent affect mass percent?

Back

The volume of solvent does not affect the mass percent of a solute, as mass percent is based on the mass of the solute and the total mass of the solution.

Front

What is the purpose of drying and weighing filter paper in experiments?

Back

To ensure all water is removed and obtain a constant mass of the precipitate, which is crucial for accurate mass measurements.

Front

What is enthalpy of reaction?

Back

Enthalpy of reaction is the heat change associated with a chemical reaction at constant pressure, usually expressed in kJ/mol.

Front

How do you calculate the enthalpy of reaction from heat evolved?

Back

To find the enthalpy of reaction, divide the heat evolved (in kJ) by the number of moles of reactants that reacted.

Front

What is a redox reaction?

Back

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

Front

What does it mean for a species to be reduced?

Back

A species is reduced when it gains electrons, resulting in a decrease in its oxidation state.

Front

What is the oxidation state of carbon in NaHCO3?

Back

The oxidation state of carbon in NaHCO3 (sodium bicarbonate) is +4.

Front

How can you determine if a reaction is a redox reaction based on oxidation states?

Back

If the oxidation states of any elements change during the reaction, it is a redox reaction.

Front

What is the significance of using an insulated cup in calorimetry experiments?

Back

An insulated cup minimizes heat exchange with the environment, allowing for more accurate measurement of heat changes in the reaction.