Temperature &
Matter
Objectives:
1. Compare Fahrenheit, Celsius, and Kelvin temperature scales.
2. Explain what is meant by absolute zero.
3. Name and describe the four states of matter.
4. Compare the physical and chemical properties of matter.
5. State the law of conservation of matter.
Key Terms:
Kelvin scale, absolute zero, matter, solid, liquid, gas, physical property,
chemical property, physical change, chemical change, law of
conservation of matter, energy, kinetic energy, potential energy, joule,
law of conservation of energy
Temperature
• There are three major systems in use for measuring temperature.
• The Fahrenheit (F) scale named after Gabriel Fahrenheit. The F scale
quickly became accepted mostly due to the availability of his
thermometers.
• The Celsius (C) scale was developed by Anders Celsius. The scale was
based on the properties of water. 0oC is the freezing point of water
and 100oC is the boiling point of water. Despite the popularity of the
F scale, the use of C quickly became the standard for scientist.
• The final scale, which is listed in the SI index for temperature, was
developed by William Thompson, Lord Kelvin. The Kelvin (K) scale is
based on the theoretical concept of absolute zero. Absolute zero is
the point where the atomic particles of matter loose their kinetic
energy. Some significant aspects of this system are:
• All the numbers are positive
• The K degree is the same size as the C degree. (Each increase in C by one
degree is and increase in one degree K)
• K = 273 + C
Matter
• Matter is anything that takes up space or more specifically
anything that has mass and volume. Density, therefore, is the
measure of matter since it is the measure of an item’s mass
per the volume that object takes up. (density = mass/volume)
The following are properties of matter.
• Density is considered a property of matter.
• It is recorded in g/cc or g/ml depending on whether it is solid or
liquid. (SI is kg/m3)
• The density of water is 1 g/ml, therefore objects with density less
than 1g/ml float and those with density greater than 1g/ml sink.
States of Matter
• Solids
• High density
• Density not readily affected by pressure
• Holds its shape without borders
• Liquids
• High density
• Density not readily affected by pressure
• Adopts the shape of the area around it
• Gas
• Low density
• Density depends on pressure
• Expands to fill its container
• Plasma
• Low density
• Density not readily affected by pressure
• Expands to fill its container
• Exists only at high temperature
Physical Properties
• Used for identification of a substance
• A physical change does not involve the rearrangement of
chemical bonds therefore do not alter the identity of a substance
• Some basic properties:
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Color
Melting point
Boiling point
Luster
Texture
Malleability
Chemical Properties
• Chemical properties are the result of the bonding
arrangement of the atoms that make up a substance
• A chemical change causes atoms to be rearranged and alters
the identity of a substance (After you burn wood it ceases to
be wood.)
• Some examples:
• Rust
• Cooked food
• Combustion
Conservation of Matter
• Matter can neither be created nor destroyed.
• This statement by Antoine Levoisier, who is considered the
father of modern chemistry, changed the way scientists
viewed nature. It's the pattern seen with the Law of
Conservation of Energy. What it clearly states is that all
chemical reactions can be broken down into their constituent
parts, measured and predicted.
• All the matter present at the start of a reaction is transferred
to the products of the reaction.
• Mass reactants = Mass products
Energy
• Energy is the term used to describe the capacity to produce
heat or to do work.
• There are two major forms of energy, Kinetic and Potential.
• Kinetic Energy (KE) is the energy of motion. When an object is in
motion, it carries kinetic energy.
• KE = (1/2mv2)
• Kinetic energy can also come in the form of mechanical energy
(energy created by the gears of a machine) and thermal energy (heat
created by the internal motion of particles of matter).
• Potential Energy (PE) is the energy of position.
• A coiled spring is an example of mechanical PE
• Water stored in a water tower is an example of gravitational PE
• Chemicals stored in batteries are all examples of electrical and
chemical PE.
Conservation of Energy
• The Law of Conservation of Energy states that "...energy can
neither be created nor destroyed, only changed from one
form to another."
• What this means is that energy is constantly changing from
one form to another. PE from the water in the water tower
changes to KE as it flows out. It may be used to turn a large
wheel which changes it to mechanical energy. The large wheel
may run a generator where the mechanical energy is being
turned into electrical PE and heat. As you can see the energy is
not lost, simply changed.
Measuring Energy
• The calorie (cal) is a common unit of measure and is the
amount required to raise 1g of water 1oC. It is also the name
given to measure of energy in food (Cal). (Cal = 1000cal=
1kcal) The SI unit for energy is the Joule named after the
physicist James Prescott Joule. The conversion for the two
common measurements is 1cal = 4.184J
• Example: An average candy bar contains 200 Calories.
• 200C x 1000cal x 4.184J = 8.36 x 105J
1
Cal
cal