Classifying MatterClassifying Matter

What phase of water is most common on Earth?

Matter: Classifying

• stopper

• test tube

• rubber band

• paper clip

• copper wire

• colored pencil

• penny

•nail •pipet •ruler •spool •bolt •beaker •toothpick •index card

Given the following materials, use classification to separate them into several groups

Physical & Chemical properties

• Matter has both physical and chemical characteristics. Any characteristic of a material that can be observed without changing the substances that make up the material is a physical property. Any characteristic that describes how one material interacts with another material is a chemical property.

Four groups based on the makeup of matter:

1. Elements are the simplest pure substances. An element cannot be changed into simpler substances by any chemical process. Elements are made up of atoms

Four groups based on the makeup of matter:

2. Compounds are pure substances made up of more than one element. Atoms of the elements in a compound are chemically bonded together to form molecules. Molecules are changed during chemical reactions.

Four groups based on the makeup of matter:

3. Mixtures consists of two or more substances mixed together but not chemically combined. Substances in mixtures can be separated by physical means.

Properties of Mixtures:

• Each substance retains all its own chemical properties.

• The substances can be present in any amount.

• The substances in a mixture can be separated by simple physical means.

Types of mixtures:

• Heterogeneous - not identical throughout - not mixed well.

• Homogeneous - identical properties throughout - well mixed.

Four groups based on the makeup of matter:

4. Solutions are special mixtures formed when one substance dissolves in another

Parts of a solution:

• Solvent - the most abundant substance in the solution.

• Solute - the least abundant substance in the solution.

Solution concentration:

• a comparison of the amount of solute dissolved in an amount of solvent. One way is to express concentration is by using percentage of mass. For example, a 5% solution of sodium hydroxide contains 5g sodium hydroxide in each 100g of solution.

Solutions have two main traits:

• Particles are too small to see.

• Particles are evenly distributed.

All solutions are not liquids

• Air is a solution of gases.

• Steel is a solution of metals

What phase of water is most common on Earth?

Most of the water on Earth is in the liquid phase. While oceans obviously come to mind, there are huge amounts of liquid water under ground. Much of this water is found in underground rivers known as "aquifers".

Phases of Matter

Matter is known to exist in 4 phases

• Solid • Liquid • Gas• Plasma

Phase change:

• The physical change of matter from one phase to another. A phase change takes place because the particles of a substance gain or lose energy, causing them to change their motion.

7 Possible Phase Changes:

• Condensation - gas to liquid

• Freezing - liquid changes to solid

• Sublimation - solid changes to gas

7 Possible Phase Changes:

• Melting - solid changes to liquid • Vaporization - liquid changes to

gas • Snow gas changes to solid • Evaporation - vaporization that

takes place at the surface of a liquid.

Phase change:

Every pure substance has a:

• Freezing point temperature - the temperature at which a liquid changes to a solid.

• Melting point temperature - the temperature at which a solid changes to a liquid.

Every pure substance has a:

• Boiling point temperature - the temperature at which a liquid boils.

Fluid

• any substance that flows. Liquids and gases are fluids.

Viscosity

• the resistance of a fluid to flow.

• Water has a low viscosity.

• Honey has a high viscosity.

Elements and Compounds

• Element cannot be changed by chemical means.

Elements and Compounds

• Atom the smallest particle of an element

• Chemical symbols - a shorthand for elements

• Compound - two or more elements chemically combined

Elements and Compounds

• Molecule - the smallest particle of a compound

• Chemical formulas - combinations of chemical symbols representing compounds

Chemical Symbols Represent Elements

• Chemical symbols can be one or two letters. The first letter is always a capital case and the second letter is always a small case. Do not get sloppy when writing chemical symbols.

What number is never used as a subscript in a chemical

formula?

11

Chemical formulas represent compounds

• Oxidation numbers are used to determine the ratio in which elements combine to form compounds.

Can you identify the atom represented here?

                             

The Bohr Model:

What makes up most of the volume of an atom?

An atom is mostly empty space.

NeutronsNeutrons

Sample Problem: How many neutrons are in a zinc atom?

atomic number - atomic mass = # neutrons

65 - 30 = 35 neutrons