AP Chemistry Flashcards: Energy Of Phase Changes

What this deck covers

This deck focuses on Energy Of Phase Changes, giving you a quick way to review the definitions, rules, and examples that matter most for AP Chemistry.

How to use these flashcards

Work through these flashcards in short sessions. Try to answer each prompt before flipping the card, then revisit any cards you miss until the explanation feels automatic.

Flashcard 1: What is the heat change when 1 mole of gas becomes a liquid?

Answer: Molar heat of condensation. Energy released per mole when gas becomes liquid.

Flashcard 2: What is the phase change from gas to liquid called?

Answer: Condensation. Phase transition from gaseous to liquid state.

Flashcard 3: What is the unit of molar heat of fusion in SI units?

Answer: Joules per mole ($\text{J/mol}$). Standard unit expressing energy per mole for fusion.

Flashcard 4: What is the formula for calculating the heat required for a phase change?

Answer: $q = m \times \text{ΔH}$. Where $q$ is heat, $m$ is mass, and $\text{ΔH}$ is enthalpy change.

Flashcard 5: What is the phase change from solid directly to gas called?

Answer: Sublimation. Direct transition from solid to gas without liquid phase.

Flashcard 6: What does the symbol $m$ represent in the heat equations?

Answer: Mass of the substance. Mass is a key variable in all heat transfer calculations.

Flashcard 7: What is the formula for calculating the heat required for a phase change?

Answer: $q = m \times \text{ΔH}$. Where $q$ is heat, $m$ is mass, and $\text{ΔH}$ is enthalpy change.

Flashcard 8: What is the enthalpy change for the transition from liquid to solid?

Answer: $-\text{ΔH}_{\text{fusion}}$. Freezing releases energy, opposite sign of fusion.

Flashcard 9: What is the heat change when 1 mole of gas becomes a liquid?

Answer: Molar heat of condensation. Energy released per mole when gas becomes liquid.

Flashcard 10: What is the energy change for converting 1 mole of solid directly to gas?

Answer: Molar heat of sublimation. Energy per mole for direct solid-to-gas transition.

Flashcard 11: What is the phase change from gas directly to solid called?

Answer: Deposition. Direct phase transition from gas to solid state.

Flashcard 12: What does the symbol $c$ represent in the formula $q = m \times c \times \text{ΔT}$?

Answer: Specific heat capacity. Energy required to raise temperature per unit mass per degree.

Flashcard 13: What is the energy change for converting 1 mole of solid directly to gas?

Answer: Molar heat of sublimation. Energy per mole for direct solid-to-gas transition.

Flashcard 14: What is the term for the heat change when 1 mole of a liquid becomes a gas?

Answer: Molar heat of vaporization. Energy change per mole for liquid-to-gas transition.

Flashcard 15: What is the energy change associated with the phase change of freezing?

Answer: Latent heat of fusion. Freezing involves the same energy as fusion but opposite direction.

Flashcard 16: What is the term for the heat change when 1 mole of a solid becomes a liquid?

Answer: Molar heat of fusion. Energy change per mole for solid-to-liquid transition.

Flashcard 17: What is the term for the heat required to convert 1 gram of a solid to a gas?

Answer: Latent heat of sublimation. Energy for direct solid-to-gas transition per unit mass.

Flashcard 18: What is the term for the energy change when a liquid turns to gas without temperature change?

Answer: Latent heat of vaporization. Energy change for liquid-to-gas transition at constant temperature.

Flashcard 19: Find the heat released by 60g of steam condensing, given $\text{ΔH}_{\text{vap}} = 2260 \text{J/g}$.

Answer: 135,600 J. $q = 60\text{g} \times 2260\text{J/g} = 135,600\text{J}$

Flashcard 20: What is the phase change from liquid to solid called?

Answer: Freezing. Phase transition from liquid to solid state.

Flashcard 21: What is the unit of latent heat of fusion in the SI system?

Answer: Joules per gram ($\text{J/g}$). Standard unit expressing energy per unit mass for fusion.

Flashcard 22: What does the symbol $q$ represent in the context of phase changes?

Answer: Heat energy. Represents the thermal energy transferred during phase transitions.

Flashcard 23: What is the typical unit for specific heat capacity?

Answer: Joules per gram per degree Celsius ($\text{J/g°C}$). Standard unit for energy per mass per temperature change.

Flashcard 24: Calculate the heat absorbed by 25g of ice melting, given $\text{ΔH}_{\text{fusion}} = 334 \text{J/g}$.

Answer: 8,350 J. $q = 25\text{g} \times 334\text{J/g} = 8,350\text{J}$

Flashcard 25: What is the unit of molar heat of fusion in SI units?

Answer: Joules per mole ($\text{J/mol}$). Standard unit expressing energy per mole for fusion.

Flashcard 26: What is the energy change for converting 1 mole of solid directly to gas?

Answer: Molar heat of sublimation. Energy per mole for direct solid-to-gas transition.

Flashcard 27: Find the heat released by 60g of steam condensing, given $\text{ΔH}_{\text{vap}} = 2260 \text{J/g}$.

Answer: 135,600 J. $q = 60\text{g} \times 2260\text{J/g} = 135,600\text{J}$

Flashcard 28: What is the phase change from solid to liquid called?

Answer: Melting. Phase transition from solid to liquid state.

Flashcard 29: What is the formula for calculating heat when temperature changes?

Answer: $q = m \times c \times \text{ΔT}$. Used for heating or cooling without phase change.

Flashcard 30: State the formula for calculating heat during a temperature change.

Answer: $q = m \times c \times \text{ΔT}$. Where $c$ is specific heat capacity and $\text{ΔT}$ is temperature change.

Flashcard 31: What does the symbol $q$ represent in the context of phase changes?

Answer: Heat energy. Represents the thermal energy transferred during phase transitions.

Flashcard 32: What phase change is associated with the latent heat of fusion?

Answer: Solid to liquid. Fusion refers to the melting process from solid to liquid.

Flashcard 33: What does the symbol $q$ represent in the context of phase changes?

Answer: Heat energy. Represents the thermal energy transferred during phase transitions.

Flashcard 34: Determine the heat change for vaporization of 30g of water, given $\text{ΔH}_{\text{vap}} = 2260 \text{J/g}$.

Answer: 67,800 J. $q = 30\text{g} \times 2260\text{J/g} = 67,800\text{J}$

Flashcard 35: Identify the phase change for the latent heat of vaporization.

Answer: Liquid to gas. Vaporization specifically describes the liquid-to-gas transition.

Flashcard 36: What is the formula for calculating heat when temperature changes?

Answer: $q = m \times c \times \text{ΔT}$. Used for heating or cooling without phase change.

Flashcard 37: What happens to the temperature of a substance during a phase change at constant pressure?

Answer: Remains constant. Energy goes into breaking bonds, not changing temperature.

Flashcard 38: Determine the heat change when a 20g ice cube melts, given $\text{ΔH}_{\text{fusion}} = 334 \text{J/g}$.

Answer: 6,680 J. $q = 20\text{g} \times 334\text{J/g} = 6,680\text{J}$

Flashcard 39: What is the energy change associated with the phase change of freezing?

Answer: Latent heat of fusion. Freezing involves the same energy as fusion but opposite direction.

Flashcard 40: Calculate the energy required to freeze 15g of water, given $\text{ΔH}_{\text{fusion}} = 334 \text{J/g}$.

Answer: 5,010 J. $q = 15\text{g} \times 334\text{J/g} = 5,010\text{J}$

Flashcard 41: What is the phase change from solid directly to gas called?

Answer: Sublimation. Direct transition from solid to gas without liquid phase.

Flashcard 42: What does the symbol $m$ represent in the heat equations?

Answer: Mass of the substance. Mass is a key variable in all heat transfer calculations.

Flashcard 43: What is the phase change from solid directly to gas called?

Answer: Sublimation. Direct transition from solid to gas without liquid phase.

Flashcard 44: What is the phase change from solid to liquid called?

Answer: Melting. Phase transition from solid to liquid state.

Flashcard 45: Calculate the heat required to vaporize 100g of water, given $\text{ΔH}_{\text{vap}} = 2260 \text{J/g}$.

Answer: 226,000 J. $q = 100\text{g} \times 2260\text{J/g} = 226,000\text{J}$

Flashcard 46: What is the term for the energy change when a liquid turns to gas without temperature change?

Answer: Latent heat of vaporization. Energy change for liquid-to-gas transition at constant temperature.

Flashcard 47: What does the symbol $\text{ΔH}$ represent in phase change calculations?

Answer: Enthalpy change. Represents the energy change per unit mass during phase transitions.

Flashcard 48: What happens to the temperature of a substance during a phase change at constant pressure?

Answer: Remains constant. Energy goes into breaking bonds, not changing temperature.

Flashcard 49: What is the phase change from gas directly to solid called?

Answer: Deposition. Direct phase transition from gas to solid state.

Flashcard 50: What is the term for the heat change when 1 mole of a solid becomes a liquid?

Answer: Molar heat of fusion. Energy change per mole for solid-to-liquid transition.

Flashcard 51: Calculate the heat required to vaporize 100g of water, given $\text{ΔH}_{\text{vap}} = 2260 \text{J/g}$.

Answer: 226,000 J. $q = 100\text{g} \times 2260\text{J/g} = 226,000\text{J}$

Flashcard 52: State the formula for calculating heat during a temperature change.

Answer: $q = m \times c \times \text{ΔT}$. Where $c$ is specific heat capacity and $\text{ΔT}$ is temperature change.

Flashcard 53: What is the term for the heat change when 1 mole of a solid becomes a liquid?

Answer: Molar heat of fusion. Energy change per mole for solid-to-liquid transition.

Flashcard 54: What is the typical unit for specific heat capacity?

Answer: Joules per gram per degree Celsius ($\text{J/g°C}$). Standard unit for energy per mass per temperature change.

Flashcard 55: What is the energy change associated with the phase change of freezing?

Answer: Latent heat of fusion. Freezing involves the same energy as fusion but opposite direction.

Flashcard 56: Calculate the energy required to freeze 15g of water, given $\text{ΔH}_{\text{fusion}} = 334 \text{J/g}$.

Answer: 5,010 J. $q = 15\text{g} \times 334\text{J/g} = 5,010\text{J}$

Flashcard 57: What is the energy change associated with the phase change of deposition?

Answer: Latent heat of deposition. Energy released when gas transitions directly to solid.

Flashcard 58: What does the symbol $c$ represent in the formula $q = m \times c \times \text{ΔT}$?

Answer: Specific heat capacity. Energy required to raise temperature per unit mass per degree.

Flashcard 59: What is the term for the heat change when 1 mole of a liquid becomes a gas?

Answer: Molar heat of vaporization. Energy change per mole for liquid-to-gas transition.

Flashcard 60: What is the phase change from liquid to solid called?

Answer: Freezing. Phase transition from liquid to solid state.

Flashcard 61: Identify the phase change for the latent heat of vaporization.

Answer: Liquid to gas. Vaporization specifically describes the liquid-to-gas transition.

Flashcard 62: Calculate the heat released when 50g of steam condenses, given $\text{ΔH}_{\text{vap}} = 2260 \text{J/g}$.

Answer: 113,000 J. $q = 50\text{g} \times 2260\text{J/g} = 113,000\text{J}$

Flashcard 63: What is the phase change called when a gas turns into a solid?

Answer: Deposition. Direct phase transition from gas to solid state.

Flashcard 64: Identify the phase change for the latent heat of vaporization.

Answer: Liquid to gas. Vaporization specifically describes the liquid-to-gas transition.

Flashcard 65: Calculate the heat required to melt 50g of ice, given $\text{ΔH}_{\text{fusion}} = 334 \text{J/g}$.

Answer: 16,700 J. $q = 50\text{g} \times 334\text{J/g} = 16,700\text{J}$

Flashcard 66: What is the term for the heat required to change 1 gram of a substance from solid to liquid?

Answer: Latent heat of fusion. Specific energy required for the melting process per gram.

Flashcard 67: What is the term for the heat required to convert 1 gram of a solid to a gas?

Answer: Latent heat of sublimation. Energy for direct solid-to-gas transition per unit mass.

Flashcard 68: What does the symbol $\text{ΔH}$ represent in phase change calculations?

Answer: Enthalpy change. Represents the energy change per unit mass during phase transitions.

Flashcard 69: What is the phase change from gas to liquid called?

Answer: Condensation. Phase transition from gaseous to liquid state.

Flashcard 70: What is the term for the energy change when a liquid turns to gas without temperature change?

Answer: Latent heat of vaporization. Energy change for liquid-to-gas transition at constant temperature.

Flashcard 71: What is the term for the heat required to convert 1 gram of a solid to a gas?

Answer: Latent heat of sublimation. Energy for direct solid-to-gas transition per unit mass.

Flashcard 72: Calculate the energy required to freeze 15g of water, given $\text{ΔH}_{\text{fusion}} = 334 \text{J/g}$.

Answer: 5,010 J. $q = 15\text{g} \times 334\text{J/g} = 5,010\text{J}$

Flashcard 73: Calculate the heat required to vaporize 100g of water, given $\text{ΔH}_{\text{vap}} = 2260 \text{J/g}$.

Answer: 226,000 J. $q = 100\text{g} \times 2260\text{J/g} = 226,000\text{J}$

Flashcard 74: What does the symbol $c$ represent in the formula $q = m \times c \times \text{ΔT}$?

Answer: Specific heat capacity. Energy required to raise temperature per unit mass per degree.

Flashcard 75: What is the phase change from liquid to solid called?

Answer: Freezing. Phase transition from liquid to solid state.

Flashcard 76: What is the heat change when 1 mole of gas becomes a liquid?

Answer: Molar heat of condensation. Energy released per mole when gas becomes liquid.

Flashcard 77: What is the unit of molar heat of fusion in SI units?

Answer: Joules per mole ($\text{J/mol}$). Standard unit expressing energy per mole for fusion.

Flashcard 78: What is the enthalpy change for the transition from liquid to solid?

Answer: $-\text{ΔH}_{\text{fusion}}$. Freezing releases energy, opposite sign of fusion.

Flashcard 79: Calculate the heat required to melt 50g of ice, given $\text{ΔH}_{\text{fusion}} = 334 \text{J/g}$.

Answer: 16,700 J. $q = 50\text{g} \times 334\text{J/g} = 16,700\text{J}$

Flashcard 80: What is the formula for calculating the heat required for a phase change?

Answer: $q = m \times \text{ΔH}$. Where $q$ is heat, $m$ is mass, and $\text{ΔH}$ is enthalpy change.

Flashcard 81: What is the energy change associated with the phase change of deposition?

Answer: Latent heat of deposition. Energy released when gas transitions directly to solid.

Flashcard 82: What is the term for the heat required to change 1 gram of a substance from solid to liquid?

Answer: Latent heat of fusion. Specific energy required for the melting process per gram.

Flashcard 83: What is the phase change from gas directly to solid called?

Answer: Deposition. Direct phase transition from gas to solid state.

Flashcard 84: What is the term for the heat required to change 1 gram of a substance from solid to liquid?

Answer: Latent heat of fusion. Specific energy required for the melting process per gram.

Flashcard 85: What is the phase change from gas to liquid called?

Answer: Condensation. Phase transition from gaseous to liquid state.

Flashcard 86: What happens to the temperature of a substance during a phase change at constant pressure?

Answer: Remains constant. Energy goes into breaking bonds, not changing temperature.

Flashcard 87: What phase change is associated with the latent heat of fusion?

Answer: Solid to liquid. Fusion refers to the melting process from solid to liquid.

Flashcard 88: What is the enthalpy change when 1 mole of water condenses?

Answer: $-\text{ΔH}_{\text{vap}}$. Condensation releases energy, opposite sign of vaporization.

Flashcard 89: What is the enthalpy change for the transition from liquid to solid?

Answer: $-\text{ΔH}_{\text{fusion}}$. Freezing releases energy, opposite sign of fusion.

Flashcard 90: What is the energy required to convert 10g of ice at 0°C to water at 0°C?

Answer: 3,340 J. $q = 10\text{g} \times 334\text{J/g} = 3,340\text{J}$

Flashcard 91: Calculate the heat absorbed by 25g of ice melting, given $\text{ΔH}_{\text{fusion}} = 334 \text{J/g}$.

Answer: 8,350 J. $q = 25\text{g} \times 334\text{J/g} = 8,350\text{J}$