Question

What is the difference between specific heat and heat capacity? What are the units for these two quantities? Which is the intensive property and which is the extensive property?

Short answer

Specific heat is an intensive property measured in J/g°C, while heat capacity is an extensive property measured in J/°C.

Step-by-step solution

Define Specific Heat

Specific heat is defined as the amount of heat required to raise the temperature of one unit mass of a substance by one degree Celsius (or one Kelvin). It is an intensive property, meaning it does not depend on the amount of the substance. The units for specific heat are typically joules per gram per degree Celsius (J/g°C) or joules per kilogram per Kelvin (J/kg·K).

Define Heat Capacity

Heat capacity is the amount of heat required to raise the temperature of a given quantity of a substance by one degree Celsius (or one Kelvin). It is an extensive property because it depends on the amount of substance present. The units for heat capacity are joules per degree Celsius (J/°C) or joules per Kelvin (J/K).

Identify Intensive and Extensive Properties

Specific heat is an intensive property, as it remains the same regardless of the amount of substance. Heat capacity, on the other hand, is an extensive property, which changes when the amount of substance changes.

Key concepts

heat capacity

Heat capacity is like the overall heat 'bucket' that a material can hold. It tells us how much heat energy is needed to change the temperature of a given quantity of the material by one degree Celsius (or Kelvin). This means if you double the amount of the material, you double its heat capacity.
Heat capacity is therefore known as an extensive property because it depends on the amount—or extent—of material present.

For example, a large pot of water has a larger heat capacity than a small cup of water, even though they're the same substance. This is why it takes more energy (or heat) to boil a big pot than a small one.

• Forms: Heat capacity varies with different substances. Each material takes different amounts of energy to change temperature.
• Application: It's crucial in choosing materials for heating and cooling applications, like cooking or building design.

intensive property

Intensive properties are like the personal qualities of a substance that do not change regardless of how much you have. Think of it as the inherent characteristics that define a material.
An intensive property remains consistent irrespective of the material's size or amount.

The specific heat of a substance is an intensive property because no matter how much of the substance you have, its specific heat remains constant. This property makes it useful since it helps predict how a substance behaves when energy is added, without needing to know the amount present.

• Examples: Besides specific heat, other intensive properties include density, boiling point, and color.
• Significance: These properties are often used in material identification and quality control.

extensive property

Extensive properties are the 'chameleons' of physical properties—they change as the amount of substance changes. Anything you can measure that grows when you have more of the material is an extensive property.
Heat capacity is considered an extensive property because it relies on the quantity of the material.

If you have a certain temperature change, a larger sample would require more heat, making this property proportional to the quantity.

• Other Examples: Mass, volume, and total charge are also extensive properties.
• Calculations: Extensive properties can 'add up.' For example, two identical soup bowls have double the total mass and volume compared to a single bowl.

units of measurement

Understanding units of measurement is essential in the world of science, helping us quantify and compare different properties accurately. For specific heat, the units typically used are joules per gram per degree Celsius (J/g°C) or joules per kilogram per Kelvin (J/kg·K).
This detail helps specify how much energy is required per unit mass for a temperature change.

Conversely, heat capacity is measured in joules per degree Celsius (J/°C) or joules per Kelvin (J/K). These units indicate the total amount of heat energy needed for a temperature change in an entire substance amount.

• Conversions: Knowing units allows us to convert these properties for different applications—for instance, from grams to kilograms.
• Consistency: Using standard units keeps calculations and communications universally understood in science and engineering.