 Chemistry is the study of the properties of matter and how matter changes.

Physical Properties – a characteristic of a pure substance that can be observed without changing it into another substance Examples:1. water changed into ice 2. sugar dissolved in water 3. bending a metal spoon

Chemical Properties – a characteristic of a pure substance that describes its ability to change into different substances Examples:1. burning wood 2. iron and oxygen turning into rust 3. cracking a glowstick

Elements – matter that cannot be broken down or changed and retain its chemical properties. An ATOM is the smallest particle of an element. Examples: HeliumHydrogenMercury CopperLeadSulfur IronGold Oxygen

Compounds – a substance made of two or more elements, chemically combined. Examples: Sodium ChloridePropane Carbon Dioxide Calcium Carbonate Nitrous OxideCarbon Monoxide

Molecular Compound – a compound made up of molecules. A molecule is a particle of matter made up of two or more atoms held together by sharing electrons. Ionic Compound – a combination of positive and negative ions. An ion is a charged particle formed when an atom or a group of atoms gains or loses one or more electrons.

Compounds are represented by MOLECULAR FORMULAS, which show the elements in the compound and the ratio of atoms. Example: Carbon Dioxide – CO 2, 1 atom carbon and 2 atoms oxygen

Mixtures – a combination of substances that are not chemically combined. Homogenous mixtures are evenly mixed so one can’t see the different parts. Heterogeneous mixtures are unevenly mixed and one can see the different parts of the mixture. Mixtures can be separated by filtering, distilling or evaporating.

All matter has MASS. Mass is an indicator of how much matter is present in an object or substance. The MASS of an object never varies. Which has more mass, a small chunk of concrete or a chunk of wood of similar volume? What’s the difference between MASS and WEIGHT? (Weight is a measure of the force of gravity on an object) We use a BALANCE to measure an objects mass.

All matter occupies space, no matter how small. Therefore, VOLUME, is a property of all matter. Volume is the amount of space an object occupies. Volume can be measured with a graduated cylinder, or by LENGTH x WIDTH x HEIGHT When matter changes shape or form, it may occupy more or less space, so, its VOLUME may change.

DENSITY – the amount of mass, or atoms, that an object contains in a given space. To measure the density of an object, you need to know its mass and its volume, as density equals mass divided by volume.  Mass is measured easily on a balance.  Volume can be calculated using length x width x height, or by water displacement. As part of Archimedes Principle, Archimedes found that an object submerged in water will displace an amount of water equal to its volume.

Again, the formula for density is: DENSITY (D) = MASS (m)/VOLUME (v) Example: If a block of lead has a mass of 10,000g and a volume of 885 cm3, what is its density? Solution: D = m/v = 10,000g/885cm 3 = 11.3 g/cm 3

When matter undergoes a change in size, shape or phase, it is a PHYSICAL CHANGE. Examples:1. broken glass 2. weathering and erosion of rocks 3. ice melting into water 4. mixing pebbles and sand 5. salt dissolved in water Physical changes DO NOT change the particles that make up matter.

In a CHEMICAL CHANGE, particles of one substance are changed in some way to form particles of a new substance that has new and different properties. Examples:iron into rust tarnished silver changes producing light/heat chemical weathering of soil In general, USUALLY, only physical changes can be easily reversed.

Law of Conservation of MASS (MATTER): In any experiment, MASS is exactly conserved, provided nothing is added or taken away.

Energy is the ability to do work and every physical or chemical change involves a change in energy. Types of Energy: Thermal energy is the total energy of the particles in an object of substance. Kinetic Energy – the energy of motion Potential Energy – the energy of position, stored energy Chemical Energy – energy stored in chemical bonds Electromagnetic Energy – travels through space as waves Electrical Energy – the energy of moving electrons

Thermal energy is the total energy of the particles in an object of substance. Temperature measures thermal energy. The most common form of energy released or absorbed is thermal energy. Endothermic change –change in which energy is taken in Exothermic change – change in which energy is given off Law of Conservation of Energy: Energy cannot be created nor destroyed. It can only be changed from one form to another.