AP Chemistry calorimetry key terms

What is calorimetry?

The measurement of heat transfer in chemical reactions.

Define specific heat capacity.

The amount of heat required to raise the temperature of 1 gram of a substance by 1 °C.

Fill in the blank: q = ____.

The heat absorbed or released, often calculated as $\displaystyle q = mc riangle T$.

True or false: Calorimetry can only measure exothermic reactions.

False, because it measures both exothermic and endothermic reactions.

What is a calorimeter?

An instrument used to measure the heat of chemical reactions.

Difference between endothermic and exothermic.

Endothermic absorbs heat; exothermic releases heat.

What is the formula for heat transfer?

The formula is $\displaystyle q = mc riangle T$ where $\displaystyle m$ is mass, $\displaystyle c$ is specific heat, and $\displaystyle riangle T$ is temperature change.

Define enthalpy change (ΔH).

The heat content change of a system at constant pressure.

True or false: A higher specific heat means a substance heats up quickly.

False, because a higher specific heat means it requires more energy to change temperature.

What is the purpose of a bomb calorimeter?

To measure the heat of combustion reactions under constant volume.

Define heat capacity.

The amount of heat needed to increase the temperature of an object by 1 °C.

Fill in the blank: In calorimetry, the surroundings are often treated as ____.

The system's heat reservoir, usually water.

Which is NOT a type of calorimeter?

Thermometer.

What is the relationship between heat and temperature change?

Heat is proportional to temperature change for a given mass and specific heat.

Difference between constant pressure and constant volume calorimetry.

Constant pressure measures enthalpy; constant volume measures internal energy.

What does a negative ΔH indicate?

The reaction is exothermic, releasing heat to the surroundings.

True or false: Calorimetry can be used to determine reaction rates.

False, because it measures heat changes, not reaction rates.

Fill in the blank: The unit of heat is ____.

Joules (J) or calories.

What is the heat of fusion?

The energy required to change a substance from solid to liquid at its melting point.

Define the term 'thermal equilibrium.'

The state where two substances reach the same temperature and heat transfer stops.

Difference between q_p and q_v.

q_p is heat at constant pressure; q_v is heat at constant volume.

What is Hess's Law?

The total enthalpy change for a reaction is the sum of changes for individual steps.

Fill in the blank: The symbol ΔH_f refers to the ____ of formation.

Standard enthalpy change of formation.

True or false: Water has a high specific heat capacity.

True, because it can absorb a lot of heat before changing temperature.

What is the heat of vaporization?

The energy required to change a substance from liquid to gas at its boiling point.