Heat Capacity and Specific Heat of Water

Heat Capacity

• Heat capacity, also referred to as thermal capacity, is a fundamental thermodynamic quantity that is a characteristic property of a substance.
• It is a measurable value that can be used to credit the purity of substances.
• The heat capacity, C, is the minimum heat absorbed by a substance to raise its temperature by one unit, 1 Kelvin or 1 Celsius.
• It is conveyed in joule (J) per kelvin (K).

Specific Heat Capacity

• Specific heat capacity (or specific heat), Cs, is the minimum heat absorbed by 1 gram of the substance to raise its temperature by one Kelvin.
• Molar heat capacity, Cm, is the heat capacity of 1 mole of a substance.

Factors Contributing to Specific Heat

• The heat capacity of a substance is a measure of the capacity of the molecules to harbor thermal energy.
• Polyatomic molecules have higher degrees of freedom because of the bonds present in them and thus have greater specific heats than their monoatomic counterparts.
• The force of attraction between particles also contributes to the specific heat capacity.

Specific Heat Capacity of Water

• The specific heat capacity of water is different in different phases: 2.100 J/g K for solid, 4.196 J/g K for liquid, and 2.030 J/g K for gas.
• The high heat capacity of water benefits both organisms and their surroundings.

Heat Capacity of Metals

• Metals have low heat capacity values when compared to water.
• The specific heat capacities of some common metals are: Copper (0.382 J/g K), Iron (0.446 J/g K), Aluminium (0.879 J/g K), and Tin (0.220 J/g K).

Calculating Specific Heat Capacity

• The specific heat capacity of a substance can be calculated using the formula: q = m x Cs x ΔT
• A sample problem is given to calculate the specific heat of a 588 gram of Iron.

Specific Heat of Metal Lab

• The specific heat of a substance can be estimated in the lab using a calorimeter and thermometers.
• The procedure involves creating a water bath, heating a metal piece, and measuring the temperature changes.

Important Notes

• Heat capacity is an important property of a substance that determines its ability to absorb and release heat energy.
• Understanding heat capacity is crucial in understanding various physical and biological processes.

Heat Capacity

• Heat capacity is a fundamental thermodynamic quantity that measures the minimum heat absorbed by a substance to raise its temperature by one unit (1 Kelvin or 1 Celsius).
• It is a measurable value that is a characteristic property of a substance and can be used to credit the purity of substances.
• Heat capacity is conveyed in joule (J) per kelvin (K) according to the International System of Units (SI).

Specific Heat Capacity

• Specific heat capacity (Cs) is the minimum heat absorbed by 1 gram of a substance to raise its temperature by one Kelvin.
• It is a measure of the capacity of the molecules to harbor thermal energy.
• Factors contributing to specific heat capacity include:
  • Degrees of freedom: the number of ways molecules can move (translational, rotational, vibrational, etc.)
  • Force of attraction: the strength of intermolecular forces between particles

Comparison of Specific Heat Capacities

• Substances can have different specific heat capacities depending on their phase (solid, liquid, gas) and molecular structure.
• Examples:
  • Argon (gas): 0.314 J/g K
  • Aluminium (solid): 0.879 J/g K
  • Methane (gas): 1.712 J/g K
  • Water (solid, liquid, gas): 2.100 J/g K, 4.196 J/g K, 2.030 J/g K

Heat Capacity of Water

• Water has a high heat capacity, which benefits both organisms and their surroundings.
• Water's high heat capacity helps to:
  • Regulate body temperature in organisms
  • Keep the environment's temperature stable

Heat Capacity of Metals

• Metals have low heat capacity values compared to water.
• Examples:
  • Copper (solid): 0.382 J/g K
  • Iron (solid): 0.446 J/g K
  • Aluminium (solid): 0.879 J/g K
  • Tin (solid): 0.220 J/g K

Calculating Specific Heat Capacity

• The specific heat capacity of a substance can be calculated using the formula: q = m * Cs * ΔT
• Where q is the heat transferred, m is the mass of the substance, Cs is the specific heat capacity, and ΔT is the change in temperature.

Laboratory Experiment

• The specific heat capacity of a substance can be estimated in the lab using a calorimeter and a heat source.
• The procedure involves:
  • Heating a metal piece to a high temperature
  • Transferring the metal to a calorimeter containing water
  • Measuring the initial and final temperatures of the water and metal
  • Calculating the specific heat capacity using the formula: q = m * Cs * ΔT