1 Matter, Change, and Energy Chemistry - The study of composition of matter and the changes that matter undergo.

1 Matter, Change, and Energy 5 Major Divisons of Chemistry I.Organic Chemistry – The study of materials that contain carbon. II.Inorganic Chemistry – The study of materials that do not contain carbon. III. Analytical Chemistry – Concerned primarily with the composition of substances. IV.Physical Chemistry – Specializes in the discovery and description of chemical substances. V.Biochemistry – The study of the composition and changes in composition of living organisms.

1 Matter, Change, and Energy The Scientific Method * The scientific method incorporates observations, hypotheses, experiments, theories, and laws. Observations - scientist make observations when they note and record facts about natural phenomena.

1 Matter, Change, and Energy The Scientific Method * The scientific method incorporates observations, hypotheses, experiments, theories, and laws. Hypothesis - a possible explanation or descriptive model used to explain the observation

1 Matter, Change, and Energy The Scientific Method * The scientific method incorporates observations, hypotheses, experiments, theories, and laws. Experiments - procedures performed to test a hypothesis where at least one condition is controlled.

1 Matter, Change, and Energy The Scientific Method * The scientific method incorporates observations, hypotheses, experiments, theories, and laws. Theories - thoroughly tested models that explain why experiments give certain results.

1 Matter, Change, and Energy The Scientific Method * The scientific method incorporates observations, hypotheses, experiments, theories, and laws. Laws - a fact or concise statement that summarizes a broad variety of observations.

1 Matter, Change, and Energy Properties of Matter * Matter is anything that has mass and takes up space. The amount of matter that an object contains is its mass. Solids – have a definite shape and a definite volume. liquids – have a definite volume but take the shape of their container. gases – fill the volume of their container and take the shape of their container. meltingevaporation condensationfreezing

1 Matter, Change, and Energy Vapor – describes a substance that although is in the gasesous state, it’s generally a solid or liquid at room temperature. sublimation

1 Matter, Change, and Energy States of Matter Website with videos. (click here)

1 Matter, Change, and Energy Matter is described by “properties”. Physical Property – a quality or condition of a substance that can be measured without changing the chemical composition of the substance.

1 Matter, Change, and Energy Matter is described by “properties”. Chemical Property – describe the changes that occur in a material when it becomes a new substance via chemical reaction.. The rusting of iron to become iron oxide is an example of a chemical change.

1 Matter, Change, and Energy Matter is described by “properties”. When ice melts it still remains the same chemically, H 2 O This is an example of a physical change.

1 Matter, Change, and Energy Mixtures A mixture consist of a physical blend of two or more substances. HeterogeneousHomogeneous * Does not have uniform composition so distinct layers are visible. Has a uniform composition is the same throughout. * A tossed salad has distinct layers so it’s heterogeneous Toothpaste has a uniform compositon and NO distinct layers, so it’s homogeneous.

1 Matter, Change, and Energy Mixtures Each distinct layer in a heterogeneous mixture Is called a phase. The boundary between Each phase is called an interface.

1 Matter, Change, and Energy Mixtures Homogeneous mixtures are uniform throughout. They consist of one phase. Homogeneous mixtures are called solutions.

1 Matter, Change, and Energy Mixtures One way to separate a homogeneous mixture such salt water into Its component substances is through a process called distillation. Diagram of simple distillation set-up without a fractionating column often used by chemists. Shown in use. 1. heat source (a Bunsen burner here) 2. distilling flask (a round bottom flask) 3. distilling head 4. thermometer 5. condenser 6. cooling water in 7. cooling water out 8. receiving flask collecting dripping distillate

1 Matter, Change, and Energy Elements and Compounds Every substance is an element or a compound. Element - The simplest form of matter that can exist under laboratory conditions. Compound – made of two or more elements. Compounds can be separated into simpler substances ONLY by chemical reactions. Cane Sugar (compound) Carbon + Water (element) (compound) Chemical Change Hydrogen + Oxygen (element) (element)

1 Matter, Change, and Energy Matter Substance Mixture of substances definite composition variable composition ELEMENTCOMPOUND HOMOGENEOUS MIXTURE HETEROGENEOUS MIXTURE

1 Matter, Change, and Energy Chemical Symbols Each element is represented by a chemical symbol. Example: H = Hydrogen ; O = Oxygen Chemical symbols can be combined to make chemical formulas. Example: H 2 O = water

1 Matter, Change, and Energy Energy Energy is the ability or “capacity” for doing work. Nearly all chemical and physical changes in nature involve the absorption or emission of energy. Energy can exist in several forms: Ex: Nuclear ; Chemical ; Radiant ; Thermal ; and Mechanical

1 Matter, Change, and Energy Energy Green plants survive by storing chemical energy. Stored chemical energy is called potential energy. Gasoline has stored potential energy. When it’s “burned” in a car motor, the chemical potential energy of the gasoline is converted to kinetic energy.

1 Matter, Change, and Energy Law of Conservation of Energy The law of conservation of energy states that energy can not be created nor can it be destroyed. However it can change forms. Just as energy is required to “fuel” a vehicle, energy is also required to “fuel” chemical reactions. Remember, a chemical reaction can never create nor destroy energy.

1 Matter, Change, and Energy Chemical Reactions In a chemical reaction, one or more substances are changed into a new substance. Reactants Products Iron + Sulfur Heat energy Iron sulfide