Chapter 2 Physical Science

Matter Preview What is Matter? Matter and Energy Properties of Matter

The world of Chemistry

Is this Chemistry?…yup!

Chemistry is… The study of matter and how it changes.

What is the matter? You are made of matter. This screen being projected on is matter. All the materials you can hold or touch is matter.

Matter is… Matter is anything that has mass and occupies space.

What do you think of when you think of the word Element?

Do you think of this element? It is sleek and stylish You can touch and hold it if you choose.

Old school belief There was a time when the only elements were like the ones listed here but…some things have changed.

Welcome to the New-School!

An Element is… A substance that cannot be broken down into simpler substances. Remember that it is simpler not smaller! And I’ll bet you are wondering how far down can you break an element?

The Atom You can break down those beautiful elements into atoms. Yes elements are made of atoms.

An Atom is… The smallest particle that has the properties of an element. We have learned to break down even the atom to begin and harvest it mighty power.

The Atom bomb The explosive energy being tapped when man seeks to dissect such a small particle. Science is not always about saving lives. Does an atom have parts too?

The makeup of an Atom An atom has these parts: Neutron with a neutral charge residing in the nucleus. Proton with a positive charge residing in the nucleus. Electron with a negative charge moving around the outside of the nucleus.

It takes Two or more. Two or more elements combine chemically to make a compound.

A Compound is… A substance made of atoms of more than one element bonded together. Acting as a unit the elements form molecules. Some couples just seem to be made for each other. CYU – Section 2.1First Half words Clicker

A Molecule is… The smallest unit of a substance that exhibits all the properties characteristic of that substance. The smallest bear cub is still a bear.

How do we express these chemicals? Chemical Formula is the chemical symbols and numbers indicating the atoms contained in a substance Confused?

Chemical Formulas Explained  Chemist keep track of combinations of atoms by using chemical formulas.  Molecular formulas shows the exact number of atoms of each element in the smallest unit of a substance.  The elements occurring in the molecule are listed by chemical symbol, with the subscripts showing how many atoms of the elements are present in each molecule.

Chemical Formulas cont.  So in a way the molecular formula is a concise expression of how many atoms of each type are present in a molecule.

Pure We think of many things when we hear the word pure.

Pure Substance Pure for many means not mixed with anything else. In science when we think of pure we must think of set or fixed composition or make- up. We must also be thinking about the properties never changing.

Pure Substance is… Any matter that has a fixed composition and definite properties.

A Mixture is.. A mixture is when you can take more than one pure substance and put them together.

Types of Mixtures Homogeneous Homo- same A homogeneous mixture is one that appears to be the same throughout. Ex. Salt & Water Heterogeneous Hetero- different A heterogeneous mixture is one in which differences can be seen. Ex. Flour & Water

Classifying Matter

Miscible is.. Describes two or more liquids that are able to dissolve into each other in various proportions. Miscible is just referring to liquids and liquids mixing Ex. Gasoline

Immiscible is.. Describes two or more liquids that do not mix into each other. Immiscible is also just referring to liquids mixing. Ex. Oil and water CYU 2.1 Second half of words quiz. Clicker

Kinetic Theory All mater is made of atoms and molecules that act like tiny particles. These tiny particles are always moving..the higher the temp. the faster they move. At the same temp. more massive particles move slower than less massive particles.

Pressure Pressure is the force exerted per unit area of surface

Viscosity is… The resistance of a liquid to flow. Viscosity is determined by the attraction between particles in a liquid. Both liquids and gases can spread so both are classified as fluids.

The States of Matter There are four states of matter. The most common state of matter in the universe is Plasma.  Solid  Liquid  Gas  Plasma

States of Matter cont.

States of Matter are Physically Different. Gas is free to spread in all directions. Gas can exert pressure Solids have rigid structure. Liquids take the shape of the container. Energy is the key!

Energy is… The ability to change or move matter. Energy can not be created or destroyed (The law of conservation of energy) Energy is either used to do work on the molecules, moving, them out of the crystal lattice at the melting point, or moving them farther from each other into gas state at the boiling point.

Changes in Phase or State As matter changes state or phase energy must be added or taken away.

Evaporation is… The change of a substance from a liquid to a gas. Energy must be added here.

Condensation is… The change of a substance from a gas to a liquid. Energy must be taken away here.

Condensation cont. This is an example of water and condensation but other substance act in the same way.

Sublimation is… The changing from gas to solid or vice versa –passing by the liquid state. This requires to add or take away great amounts of energy at once.

Through all the changes  Mass stays the same!

The Law of Conservation of Mass

Chemical Property is…  The way a substance reacts with others to form new substances with different properties.

Reactivity is..  The ability of a substance to combine chemically with another substance.

Physical Properties is…  Characteristics of a substance that can be measured or observed without changing the composition of substance.  Using your senses you can observe the shape, color, odor, and texture.  Other physical properties: melting point, boiling point, strength, hardness, ability to conduct electricity, or heat & density.

Melting Point  The temperature at which a solid becomes a liquid.

Boiling Point  The temperature at which a liquid becomes a gas.

Density  Density is the mass per unit volume of a substance.  Density is a physical property  D= m/V

Buoyancy  The force with which a more dense fluid pushes a less dense substance upward.  In short its ability to float.

Chemical Change  A change that happens when a substance changes composition by forming one or more new substance.  Fireworks are examples of chemical changes.  Fire works Fire  More on that More

Physical Changes  A physical change is a change in physical form or properties of a substance that occurs without a change in composition.  Physical Physical

Which is an example of a physical change in the paper?