sign in sign up
<<
Home , Strange matter

Properties of

What is matter? Matter is anything that takes up space!!! What are the three states of matter??? The three states of matter are , , and !

States of Matter Gases, liquids and solids are all made up of microscopic particles, but the behaviors of these particles differ in the three phases. The following figure illustrates the microscopic differences.

Microscopic view of a Microscopic view of a Microscopic view of a . . . Note that:  Particles in a: o gas are well separated with no regular arrangement. o liquid are close together with no regular arrangement. o solid are tightly packed, usually in a regular pattern.  Particles in a: o gas vibrate and move freely at high speeds. o liquid vibrate, move about, and slide past each other. o solid vibrate (jiggle) but generally do not move from place to place. Liquids and solids are often referred to as condensed phases because the particles are very close together.

The following table summarizes properties of gases, liquids, and solids and identifies the microscopic behavior responsible for each property. Some Characteristics of Gases, Liquids and Solids and the Microscopic Explanation for the Behavior gas liquid solid assumes the shape and assumes the shape of retains a fixed volume volume of its the part of the and shape container container which it rigid - particles locked particles can move past occupies into place one another particles can move/slide past one another compressible not easily not easily lots of free space compressible compressible between particles little free space little free space between particles between particles flows easily flows easily does not flow easily particles can move past particles can rigid - particles cannot one another move/slide past one move/slide past one another another

In shortly speak: Solid state Solids have three main properties: 1. It has a definite shape. 2. It has a definite mass. 3. It has a definite volume. This means that a solid will always look the same, take up the same amount of space, and have the same amount of molecules in it.

Liquid state Liquids have three main properties: 1. It does not have a definite shape. 2. It has a definite mass. 3. It has a definite volume. This means that liquids will always take up the same amount of space and have the same amount of molecules in it. However, because it does not have a definite shape, it takes the shape of its container.

Gas state Gases have three main properties: 1. It does not have a definite shape. 2. It does not have a definite mass. 3. It does not have a definite volume.

This means that a gas does not always take up the same amount of space, nor does it weigh the same all the time. Like liquids, gases take the shape of their containers. However, they will fill the space they are given. That is why they don't always take up the same amount of space!!

properties of matter There are four different properties of matter. They are weight, volume, mass, and density.

Mass The most important one is mass. Mass is the amount of matter in an object and it never changes unless matter is taken out of the object. Mass also has a direct relationship with inertia. Inertia is the resistance of motion of an object. If an object has a greater mass, then it has a greater inertia. Also, you can find mass by measuring it on a triple beam balance.

(Q)Does the man on top of Mount Everest have a greater or lesser mass then he would in Death Valley?

Volume Volume is another general property of matter. Anything that takes up space has volume. In fact, volume is the amount of space an object takes up. You can find a straight-edged object's volume by measuring the Length x Width x Height. For irregular shaped objects, you'd probably want to use a graduated cylinder. Liters and milliliters are used to measure the volume of liquids, while cubic centimeters are used to measure solids.

(Q)If the cube is 5cm long, 5cm wide, and 5cm tall; what is the volume of the object?

Density The third general property of matter is density. Density is very important because it enables you to compare different objects. For instance, water has a density of 1 gram/cc and wood is 0.8 grams/cc. Therefore, wood will float in water because it's density is less than that of water. The equation for density is Density=Mass/Volume. Also, if you split an object in half, it will still have the exact same density.

(Q)If the mass of the car is 2000kg, and the volume is 1000cc, then what is the density? (A)The density would be 2kg/cc. Don't forget, density equals mass divided by volume.

Weight Weight is the fourth general property of matter. It is defined as the measure of force of attraction between objects due to gravity. Gravity is what keeps you and me on the ground. In fact, gravity exists between you and your computer. You are attracted to it by gravity. You don't feel the attraction because the computer's mass is so small. The earth, on the other hand has a very large mass. That's why you are attracted to the ground. Weight, unlike mass, changes with location. The farther you are from the center of the Earth, the less you weigh. The metric unit for weight is the Newton, even though in America the most common unit is the pound. The equation for weight is Weight=Mass x Acceleration due to gravity, but I personally think the easiest one is for every kilogram of mass, there's 9.8 Newton of weight.

(Q)If the mass of buck is 125kg, then what is the weight in newtons on Earth?

(A)It would weigh 1,225N. This is because there's 9.8 newtons on Earth for every one kilogram.

PROPERTIES OF MATTER - CHEMICAL AND PHYSICAL Physical properties - depends only upon matter itself, the identity of the substance does not change. Physical properties can be measured using physical senses. Examples: color, mass, size, density, magnetic, point, point, texture, shape. Chemical properties - those things that describe the events which occur when two materials react with each other. Examples: Was heat, light, sound, or some other form of energy generated? Did a reaction take place at all (if not, the materials are non-reactive - which is a chemical property)? Were gases formed? Was it endothermic or exothermic? The chemical properties of an element are determined by the number of valence electrons it has. Example: a rusting nail 4 Fe + 3 O2 ------> 2 Fe2O3 iron oxygen iron(III) oxide New substance formed which has its own set of physical and chemical properties, but, can be broken back down into the elements which formed it.

Intensive Versus Extensive Properties

Physical properties of matter are categorized as either Intensive or Extensive: o Intensive - Properties that do not depend on the amount of the matter present. . Color . Odor . Luster - How shiny a substance is. . Malleability - The ability of a substance to be beaten into thin sheets. . Ductility - The ability of a substance to be drawn into thin wires. . Conductivity - The ability of a substance to allow the flow of energy or electricity. . Hardness - How easily a substance can be scratched. . Melting/ Point - The temperature at which the solid and liquid phases of a substance are in equilibrium at atmospheric pressure. . - The temperature at which the pressure of a liquid is equal to the pressure on the liquid (generally atmospheric pressure). . Density - The mass of a substance divided by its volume o Extensive - Properties that do depend on the amount of matter present. . Mass - A measurement of the amount of matter in a object (grams). . Weight - A measurement of the gravitational force of attraction of the earth acting on an object. . Volume - A measurement of the amount of space a substance occupies. . Length

CHANGES IN MATTER - PHYSICAL AND CHEMICAL

 Physical change: change in physical properties - a change in shape, size, or state without a change in actual composition.  - it involves changes in one or more physical properties of a substance but not in the identifying chemical properties or molecular composition of the substance.  - Example: breaking a rock, melting ice, , freezing water.

 Chemical change: Change in which a substance becomes another substance with different properties.  - Example: souring of milk, silver tarnishing, electrolysis of water  - an energy change always accompanies a chemical change - loss or gain of heat, light, or some other form of energy.

Physical Changes . Changes in matter that do not alter the identity of the matter itself. . For example: 1. Size 2. Shape 3. State - solid liquid gas 4. Dilutions

Chemical Changes 3. Changes that do alter the identity of a substance. 4. For example: 1. Iron rusting

4 Fe(s) + 3 O2(g) 2 Fe2O3 � 3 H2O 2. Wood burning 3. Copper turning to brass

KINETIC THEORY OF MATTER To understand the different states in which matter can exist, we need to understand something called the Kinetic Molecular Theory of Matter. Kinetic Molecular Theory has many parts, but we will introduce just a few here. One of the basic concepts of the theory states that atoms and molecules possess an energy of motion that we perceive as temperature. In other words, atoms and molecules are constantly moving, and we measure the energy of these movements as the temperature of the substance. The more energy a substance has, the more molecular movement there will be. An important point that follows this is that the amount of energy that atoms and molecules have (and thus the amount of movement) influences their interaction with each other. Unlike simple billiard balls, many atoms and molecules are attracted to each other as a result of various intermolecular forces such as hydrogen bonds, van der Waals forces, and others. Atoms and molecules that have relatively small amounts of energy (and movement) will interact strongly with each other, while those that have relatively high energy will interact only slightly, if even at all, with others. How does this produce different states of matter? Atoms that have low energy interact strongly and tend to “lock” in place with respect to other atoms. Thus, collectively, these atoms form a hard substance, what we call a solid. Atoms that possess high energy will move past each other freely, flying about a room, and forming what we call a gas. As it turns out, there are several known states of matter; a few of them are detailed below.

Solids are formed when the attractive forces between individual molecules are greater than the energy causing them to move apart. Individual molecules are locked in position near each other, and cannot move past one another. The atoms or molecules of solids remain in motion. However, that motion is limited to vibrational energy; individual molecules stay fixed in place and vibrate next to each other. As the temperature of a solid is increased, the amount of vibration increases, but the solid retains its shape and volume because the molecules are locked in place relative to each other.

Liquids are formed when the energy (usually in the form of heat) of a system is increased and the rigid structure of the solid state is broken down. In liquids, molecules can move past one another and bump into other molecules; however, they remain relatively close to each other like solids. Often in liquids, intermolecular forces (such as the hydrogen bonds) pull molecules together and are quickly broken. As the temperature of a liquid is increased, the amount of movement of individual molecules increases. As a result, liquids can “flow” to take the shape of their container but they cannot be easily compressed because the molecules are already close together. Thus liquids have an undefined shape, but a defined volume.

Gases are formed when the energy in the system exceeds all of the attractive forces between molecules. Thus gas molecules have little interaction with each other beyond occasionally bumping into one another. In the gas state, molecules move quickly and are free to move in any direction, spreading out long distances. As the temperature of a gas increases, the amount of movement of individual molecules increases. Gases expand to fill their containers and have low density. Because individual molecules are widely separated and can move around easily in the gas state, gases can be compressed easily and they have an undefined shape.

Plasmas are hot, ionized gases. Plasmas are formed under conditions of extremely high energy, so high, in fact, that molecules are ripped apart and only free atoms exist. More astounding, plasmas have so much energy that the outer electrons are actually ripped off of individual atoms, thus forming a gas of highly energetic, charged ions. Because the atoms in exist as charged ions, plasmas behave differently than gases, thus representing a fourth . Plasmas can be commonly seen simply by looking upward; the high energy conditions that exist in stars such as our sun force individual atoms into the plasma state. As we have seen, increasing energy leads to more molecular motion. Conversely, decreasing energy results in less molecular motion. As a result, one prediction of Kinetic Molecular Theory is that if we continue to decrease the energy (measured as temperature) of a substance, we will reach a point at which all molecular motion stops. The temperature at which molecular motion stops is called absolute zero and has been calculated to be -273.15 degrees Celsius. While scientists have cooled substances to temperatures close to absolute zero, they have never actually reached absolute zero. The difficulty with observing a substance at absolute zero is that to “see” the substance, light is needed, and light itself transfers energy to the substance, thus raising the temperature. Despite these challenges, scientists have recently observed a fifth state of matter that only exists at temperatures very close to absolute zero. Bose-Einstein Condensates represent a fifth state of matter only seen for the first time in 1995. The state is named after Satyendra Nath Bose and Albert Einstein who predicted its existence in the 1920’s. B-E condensates are gaseous superfluids cooled to temperatures very near absolute zero. In this weird state, all the atoms of the condensate attain the same quantum-mechanical state and can flow past one another without friction. Even more strangely, B-E condensates can actually “trap” light, releasing it when the state breaks down. Several other less common states of matter have also either been described or actually seen. Some of these states include liquid , fermionic condensates, super fluids, super solids and the aptly named strange matter.

Transitions and Equilibrium

The States of Matter, Molecular Stickiness, and Thermodynamics

The phases of matter represent 'classes' of the type of molecular motion found at different temperatures. When the temperature is low, the motion of molecules is dominated by the fact that they stick together, and the result is a phase of matter that is rigid and dense. When the temperature is high, the motion of the molecules is dominated by their translational energy, so intermolecular forces can almost be ignored. At intermediate temperatures, molecules translate but still stick together.

Solids (tightly-bound molecules)

 At low temperatures the nuclei of the atoms of a solid vibrate about an equilibrium position but are trapped in their lattice positions, unable to flow or diffuse.  The intermolecular forces are stronger than the average thermal energy of the system.  Long range radial and angular order (structure) are usually present in single solids. Even amorphous solids have relatively good spatial ordering, especially over small distances, (10-100 molecules) Liquids

 As the binding energy to the lattice site is overcome by thermal energy, the molecules in the solid may slip past each other but maintain close contact.  The overall substance is fluid, but not very compressible.  Some long range radial ordering persists, but usually only over the size of a few molecular diameters

Gases (free motion)

 Gases are described by the Kinetic Theory of Gases. In this limit, gas molecules have negligible size, have no appreciable intermolecular forces, and are in continuous, random motion.  Gases have mean free paths that are larger than molecular diameters, i.e. they are usually isolated but occasionally have collisions  The state of a gas is universally, if approximately, described by the Ideal Gas .

Phase transition Our understanding of surface tension was made more complete by our understanding of intermolecular forces, i.e., the energetics of making and breaking of intermolecular bonds between molecular 'neighbors'. Such energies can be determined experimentally by calorimetry, or the measure of the heat flow during a chemical or physical process.

The heating of a sample of water from -25 to 125 oC involves both the heat capacities of the pure phases but also the enthalpies of the melting(fusion) and boiling() of the water.

The enthalpy of the melting reaction and the boiling reaction are both positive (endothermic). {Melting is sometimes called fusion}

Phase Transitions take energy because of the breaking (or making) of intermolecular 'bonds'.

Phase Transitions at a given temperature can reach equilibrium, i.e. steady state. If you put any liquid in a sealed vessel and wait long enough, the liquid will come into equilibrium with its vapor, and a constant (steady; dependent only of the temperature) equilibrium vapor pressure will be established

Phase diagram Every substance can exist as a Solid, Liquid, or Gas, and so Solid / Gas and Solid / Liquid and Liquid / Gas equilibria occur for all substances at some temperature and pressure. The phase diagram is a plot of all the equilibrium curves between any two phases on a pressure temperature diagram:

 The shape of the Phase Diagram is Different in details depending on the substances.  There is only one place where all three phases of a pure substance are at equilibrium. This is called the [POINT A on the diagram]. (The aliens, when we meet them, will know the pressure and temperature of the triple point of water, do you?)  The liquid / vapor equilibrium curve ends at a temperature and pressure where gases and liquids are indistinguishable fluids. This is called the critical point [POINT B on the diagram] and therefore has a critical temperature and a critical pressure.  At POINT C and POINT D on the diagram, two phases are in equilibrium and off the line entirely there is only one stable phase of the substance.

LAW OF CONSERVATION OF MATTER Matter cannot be created nor destroyed, it can only be changed from one form to another.

matter and energy are interchangeable according to E=mc2 (E=amount of energy, m= amount of matter, c=constant equal to the velocity of light) The Law of Conservation of Matter is why we must balance a chemical equation : C + O2 ------> CO2 (reactants) (product) - The total number of atoms in the reactants is equal to the total number of atoms in the product. - Two pieces of matter cannot occupy the same space at the same time. Example: When you get into a bathtub filled with water, the water level rises (water displacement).