The Nature of Matter

The Properties of Matter

What is matter?

• Easier to describe than to define. It is the “stuff” that makes up all objects.

• Matter is anything that has mass and takes up space. Mass is the measure of the amount of matter in an object.

• Different types of matter – different characteristics or properties (color, odor, ability to dissolve, temperature at which a substance melts or boils)

Two classifications of matter

• Matter may be a substance – a particular kind of matter, all samples of which have the same makeup and properties. A substance is a pure sample of matter. Examples, gold, salt, silver, sugar.

• Matter may be a mixture – a combination of two or more kinds of matter that can be separated by physical means. The different kinds of matter in a mixture keep their own properties.

What are substances?

• There are two kinds of substances: elements and compounds

• Elements are substances that cannot be made into simpler substances by ordinary means. Elements are made up of only one type of atom. There are currently 117 different elements, 90 occur naturally, most in compounds.

What is a compound?

• A compound is a substance that is made up of two or more elements chemically combined in a fixed proportion. Water, salt and sugar are all compounds. Compounds keep their properties during some changes. But compounds can be broken down into their individual elements.

What about mixtures?

• Mixtures can be uniform or non-uniform.

• Most matter occurs as mixtures. Some mixtures are uniform throughout like brass. It is a uniform mixture of zinc and copper. However, non-uniform mixtures vary in composition and properties from one point in the mixture to another.

The Nature of Matter

Four states of matter

Four forms or states of matter• Solid - definite volume, definite shape• Liquid – definite volume, no definite shape• Gas – no definite shape or volume• Plasma – a hot gas with electrically charged

particles, so no definite shape or volume

Solids

• 2 groups of solids– Crystalline – solid

whose particles are arranged in regular, repeating 3D patterns

– Amorphous – solid whose particles lack a regular, repeating order. All particles are jumbled together

Solids, continued

• Particles are very close together in solids

• Particles are held together by strong forces of attraction

• Particles in matter are always in motion

• In a solid, particles vibrate about fixed positions but do not move around freely

Liquids

• Particles in a liquid are held together by strong forces of attraction

• But forces of attraction are not strong enough to hold liquids in a definite shape

• Particles in liquids are always in movement, slipping past one another in non-fixed positions, so a liquid will flow and take the shape of its container

Viscosity

• The resistance of a fluid to flow. Ex. Molasses is more viscous than water.

Gases

• Particles in a gas are very far apart compared to solids and liquids

• Forces between gas particles are very weak.

• Gas particles move quickly and collide with one another often. As a result gases mix together easily

Plasma

• The sun and other stars are in a plasma state

• Particles move very fast and shake violently

• Plasma contains positively charged ions and free floating electrons so it conducts electricity

• Plasma only exists in extremely high temperatures, (2000°C) rarely on earth

VOCABULARY

• CONDENSATION – gas to a liquid

• SUBLIMATION – solid to a gas without going through the liquid phase

• FREEZING – liquid to a solid

• EVAPORATION – liquid to a gas

• MELTING – solid to a liquid

Kinetic Molecular Theory

• As a substance is heated the molecules begin to vibrate and thus move faster. This movement causes the bonds to break as the various phases are moved through.

• ABSOLUTE ZERO - TEMPERATURE WHERE ALL MOLECULAR MOTION STOPS.

Flow chart of states of matter

• Draw a visual representation to illustrate each of the topics.

• Use correct vocabulary words to describe the meaning

• freezing• melting• condensation• evaporation• sublimation• absolute zero

Boyle’s Law

• As the pressure of a gas increases, it’s volume decreases.

• P1V1 = P2V2

Charles’ Law

• As temperature increases the volume of a gas increases.

Periodic Chart

What does all of that stuff mean?

How is the Periodic Chart arranged?

• Periods – A row of the table (right to left)• Groups – A column (up & down) • Metals • Non-metals • Metalloids• Lanthanides – elements 58-71 • Actinides – elements 90-103

What is on a block in the chart?

• Name• Elemental

abbreviation - symbol• Atomic Number

• Atomic mass• Valence electrons –

number and placement

• Hydrogen, Sodium, Mercury

• H, Na, Hg• 1, 11, 80 - # of

protons in nucleus• 1.0008, 22.990, 200.59• Electrons in the

outermost shell of an atom, from 1 to 8

What is an atom?

• An atom is composed of subatomic particles with a nucleus at the center surrounded by electrons

• Neutrons and protons in the center

• Electrons orbit the nucleus in shells

Scanning tunneling microscope image of uranium atoms

First picture of thorium atoms - SEM

Structure and mass

• Protons (+ charged nucleons) and neutrons (neutral charged nucleons) have about the same mass

• The mass of protons and neutrons is about 1800 times the mass of an electron

• Electrically neutral atom if protons = electrons

• Ion if # of electrons is ≠ the # of protons

What is an molecule?

• Two or more elements combined in a proportional way

• Here is a model for methane CH4 and ammonia NH3