Energy, Temperature, and Temperature Conversions in GOB Chemistry

Energy, Temperature, and Heat

Definitions and Key Concepts

Understanding the concepts of energy, temperature, and heat is fundamental in GOB Chemistry, as these properties influence chemical reactions and physical changes.

• Energy: The capacity to do work or to produce heat.

• Thermal Energy: A form of energy related to the kinetic and potential energies of atoms in an object.

• Temperature: The average kinetic energy of the particles in an object; it is a measurement of thermal energy.

• Heat: The flow of thermal energy from an object at a higher temperature to an object at a lower temperature.

Example

Given two cubes at different temperatures, the cube with the higher temperature has more thermal energy. Heat will flow from the hotter cube to the cooler cube until thermal equilibrium is reached.

Practice Application

• When comparing containers of water at different temperatures, the container with the highest temperature will have the greatest flow of thermal energy.

Temperature vs. Heat

Comparison

• Temperature is a measure of the average kinetic energy of particles in a substance.

• Heat is the transfer of thermal energy between objects due to a temperature difference.

• Objects with the same temperature can have different amounts of heat if their masses differ.

Temperature Conversions

Units of Temperature

Temperature can be measured in several units:

• Celsius (°C)

• Fahrenheit (°F)

• Kelvin (K)

Conversion Formulas

To convert between temperature units, use the following equations:

• From Celsius to Kelvin: $K = ^\circ C + 273.15$

• From Celsius to Fahrenheit: $F = 1.8(^\circ C) + 32$

• From Fahrenheit to Celsius: $^\circ C = \frac{F - 32}{1.8}$

Example

One of the hottest recorded days in the country was 128°F in Lake Havasu City, Arizona. If the melting point of phosphorus is 44.15°C, would it exist as a solid or liquid on this extremely hot day?

• Convert 128°F to Celsius: $^\circ C = \frac{128 - 32}{1.8} = 53.3$ liquid

• Since 53.3°C > 44.15°C, phosphorus would be a liquid.

Practice Application

• To find the temperature at which Fahrenheit equals Celsius, set $F = ^\circ C$ and solve: $F = 1.8(^\circ C) + 32$ Set $F = ^\circ C$: $^\circ C = 1.8(^\circ C) + 32$ Solve for $^\circ C$: $^\circ C - 1.8(^\circ C) = 32$ $-0.8(^\circ C) = 32$ $^\circ C = -40$ So, -40°C = -40°F

Temperature Conversion Table

The following table summarizes the main temperature conversion formulas:

Conversion	Formula
Celsius to Kelvin	$K = ^\circ C + 273.15$
Celsius to Fahrenheit	$F = 1.8(^\circ C) + 32$
Fahrenheit to Celsius	$^\circ C = \frac{F - 32}{1.8}$