Matter = anything that occupies space and has mass = may exist as a - pure substance (only one kind of matter) either an element or compound - mixture (two or more kinds of matter)

SO…. is called CHEMISTRY!! The study of matter Its composition and properties How it can be changed into something new is called CHEMISTRY!! SO…. To gain an understanding of the how some things work, why oil and water don’t mix, why salt and sugar dissolve in water, how solutions are made or how pH is measured a basic understanding of some the basic principles of chemistry is necessary re

Areas of Chemistry General Chemistry Organic Chemistry Biochemistry Inorganic Chemistry Environmental Chemistry Physical Chemistry Nuclear Chemistry

Pure Substance = sample of matter with only one component Elements = pure substances that cannot be broken down into simper substances with different properties Compounds = a pure substance made up of two or more elements that are chemically combined in a fixed proportion by mass

What are Elements Made Of? Atoms are the basic structural unit Are the smallest particle of an element Are so small that they cannot be visualized even w/sophisticated microscopes About 2 billion atoms will fit on a period. All the atoms of given element are essentially the same

Elements Building blocks of matter Simplest type of pure substances from which more complex matters are built Presently 114 known elements 90 of them are naturally occurring, rest are man-made Every element has its own unique set of physical and chemical properties 90% of the universe is hydrogen and 70% of the earth’s crust is made up of oxygen and silicon Many are necessary in biological systems

Elements in percent by mass in (a) Earth's crust (including oceans and atmosphere) and (b) the human body.

Elements on the Periodic Table What is the periodic table? -a chart that shows all of the known elements -give information about each element

Periodic Table

Why Know About the Periodic Table?? The periodic table is the most important chemistry reference there is.  It arranges all the known elements in an informative array. Its main use is to predict the chemical properties of an element based on where it is located on the table. People familiar with how the table is put together can quickly determine a significant amount of information about an element.

Some Common Elements & Their Symbols

Think Inside the Box 6 C Carbon When you look at the periodic table, you should notice that each box represents a different element, and each box contains vital information about the element, Name symbol atomic number atomic mass 6 C Carbon 12.011

The top number is the atomic number. Every element has its own unique atomic number.

The large letter is the element's symbol Just below that is the element's name. Each element has its own unique symbol and name.

Below the name is the element's atomic mass. The atomic mass essentially gives you an estimate of how massive one atom of that element is

3 Main Categories of Elements Metals Non-Metals Metalloids

Metals On the left side of the table All are solid except for mercury Described as shiny, ductile (most metals can be drawn out into thin wires), malleable (most metals can be hammered into thin sheets ) All are good conductors of electricity All are good conductors of heat

Non-metals On the right side of the periodic table Some are solid, some are gases. Bromine is a liquid Under most conditions are not good conductors of heat or electricity

Metalloids (semi-metals) Elements along the stair-step line These elements display the properties of metals and non-metals, depending upon the conditions.

Units of a Compound – they are all the same Compounds Compounds are pure substances made up of 2 or more different elements in a different proportion. Each is put together so that every unit of that compound is identical to every other unit They are different from every other compound Units of a Compound – they are all the same

Examples of Compounds Water - made up of hydrogen and oxygen Carbon dioxide – made up of carbon and oxygen Rust – made up of iron and oxygen Sugar – Made up of carbon, hydrogen and oxygen

Naming Compounds Chemical formula – describes exactly what elements and the number of atoms of each element occurs in the smallest particle of that compound. We identify what elements are present by their symbol How many of those elements present are indicated by the subscript following the symbol.

Chemical Formulas Water = H20 means that each unit of water contains 2 atoms of hydrogen and one atom of oxygen Sugar (sucrose)= C12H22011 How many atoms of each element are in a unit of sugar?

C12H22011

Mixtures = a combination of two or more substances in which each retains its own identity May be a homogenous mixture OR - May be a heterogeneous mixture

Mixtures Homogeneous mixtures - A mixture of two or more components that is uniform throughout. Every portion of the sample is identical Components cannot be filtered out or separated out or will not settle out - Can exist as a solid, liquid or gas For example brass (a mixture of zinc & copper.) Salt water (Sodium chloride dissolved in water) air (a uniform mixture of N2, O2, CO2 and trace gases)

Mixtures Heterogeneous mixtures – have 2 or more components - components have distinct regions with definite boundaries - can be separated by some physical property - can exist as liquids or solids For example: Soil – bits of sand, black soil, organic matter Blood - appears homogeneous but it is actually a heterogeneous mixture of red and white blood cells that are visible under a microscope.

In-between Classification Colloid or colloidal dispersion - mixture that is not quite heterogeneous and not quite homogeneous Example – milk is a colloid. The particles are too small to be seen unaided but are small enough that they will not settle out Others = fog, smoke, whipped cream, mayonnaise, marshmallows

Fat In Milk (Globules Magnified)                                 Skim-milk Whole Milk Cream

Another type of Mixture Suspension – where particles are large enough that they will eventually settle out mixture in which the particles of one substance are scattered in another without dissolving Example – making a clay pot. The clay particles in the mixture eventually settle out.

Differentiating between mixtures A true solution, will appear clear when a light is shown through it.

Differentiating between mixtures Colloidal dispersion - very small particles spread throughout the liquid which are large enough to reflect light, but not large enough to be seen individually. may look either clear or cloudy in ordinary room light. particles in remain dispersed in the liquid and will not settle out.

Matter =easiest categorized by it’s physical states either a solid, liquid or gas

States of Matter Solids – have a definite shape and volume Individual particles are arranged very close together so that there is very little motion and no room for compression Crystalline solids – particles arranged in regular, systematic patterns (sugar, salt) Amorphous solids – some freedom of motion of the particles ( glass, rubber, wax)

Physical States of Matter Liquids – have fixed volume but variable in shape. Particles are not held together as rigidly as the solid state They can slide past one another so the sample is said to flow or be fluid They take on the shape of the container Volume of sample remains constant

Physical States of Matter Gases – have no volume or fixed shape Particles are not attracted to each other but rather expand to fill any conatiner Particles are in constant random motion and move about independently Distance between them is greater than in a solid or liquid. Can be compressed into a smaller space, within limits

Matter All types of matter contain energy. More specifically kinetic energy = the energy of motion How much kinetic energy is dependent on the mass of the individual particles and the velocity at which they are moving.

The Amount of Kinetic Energy Solid – very little kinetic energy Liquid - more random movement of particles so there is more energy Gas – particles move constantly and independently. Generally – has more energy than a solid or liquid

Conversion From One Physical State to Another Ice to Water to Gas Solid - below 0ºC (freezing point) Liquid – between 0ºC and 100ºC (melting point) Gas (steam) – converted to once it reaches 100ºC (boiling point)

Phase Changes as Temperature Increases

Temperature Is the measure of the average Kinetic Energy of the particles in a particular sample Temperature rises when energy is added. When energy leaves, temperature decreases

Properties Of Matter

When a physical property is changed we say it is a physical change Physical properties– those that can be observed or measured without changing the composition of the sample of matter. When a physical property is changed we say it is a physical change A physical change is a change in the form of matter but not in its chemical identity. No new compounds are formed during a physical change.

What is a Physical change? Melting is a physical property When ice melts and becomes water this is a physical change.

What about tearing a big piece of paper into smaller pieces or chopping wood into smaller pieces? Physical change Have only made the size of the sample smaller

Chemical properties – describes the ability of a sample of matter to be converted into a different sample of matter All of the original substance must be accounted for Law of Conservation of Matter – matter may not be created or destroyed in a chemical transformation. This chemical change (transformation) involves the rearrangement of the atoms to form some new type(s) of matter.

Chemical Changes Involve energy The energy holds all the parts of the substance together like glue Before they are changed into something new the pieces have to be pulled apart – this requires energy When they are reassembled again into a new substance the “glue” or energy holds them together

Questions to ask – Does it burn in air? Does it decompose when heated? What happens when it is placed in acid? What other chemicals will the sample of matter react with and what is produced? Chemical changes are usually irreversible. New compounds are formed during a chemical change

Physical and chemical properties… Describe a sample of matter In most cases is does not matter what the size of the matter is it will still have the same properties These properties are called intensive properties

Describing an Iron Nail . Physical Properties = heavy, malleable, ductile, silvery-white color and can take and retain a magnetic field Chemical Properties = The rusting of iron is an example of a chemical change. Reaction = moisture and oxygen in the air forms a compound called an oxide The rust has a different chemical composition than the initial iron 2

Burning Candle Chemical or Physical Change?

Bolt in Strong Acid Chemical or Physical Change?

Penny in Solution Chemical or Physical Change?

Fireworks Chemical or Physical Change

Crushing/Grinding Chemical or Physical Change?

Cooking an egg Chemical or Physical Change?

Breaking Glass before after Breaking Glass Chemical or Physical Change? Breaking Glass before after

Chopping Food Chemical or Physical Change?