Unit 2 - Chemistry and Matter

Chemistry the study of composition, structure, and properties of matter and the changes it undergoes.

Chemicals the substances that make up matter

Chemists study the composition and behavior of matter, and they modify materials for new purposes

Careers in Chemistry Doctors Environmental Testing Water Analysis Solar Engineers Electrochemists Quality Control Biotechnician Pharmacy Research Hazardous Waste

Matter anything that has mass and takes up space Everything is made up of matter

Pure Substance matter that has uniform and definite composition All samples of one substance have identical physical properties

Physical Property quality or condition of a substance that can be observed or measured without changing the substance’s composition Intensive property= doesn’t depend on size Extensive property= depends on size examples

Physical Change alteration of a given substance without changing its composition examples

Chemical Reaction one or more substances changing to a new substance Reactants form Products

Chemical Reaction

Chemical Reaction

Chemical Reaction http://www.youtube.com/watch?v=ODf_sPexS2Q

Chemical Property ability of a substance to undergo a chemical reaction and form a new substance.

Chemical Changes examples

Chemical vs. Physical In chemical rxns energy is absorbed or released, there is a change in color or odor, and the change can’t be reversed physically while most physical changes can be reversed

Physical and Chemical Properties

Physical and Chemical Changes http://www.youtube.com/watch?v=qqqmFFCwd7k

Physical and Chemical Changes Energy Changes occur with physical and chemical changes Endothermic – energy is absorbed (T drops) Exothermic – energy released (T rises)

Law of Conservation of Mass

Law of Conservation of Mass states that in any physical or chemical change, mass is neither created nor destroyed. It is conserved so that the mass of products equals the mass of the reactants.

Law of Conservation of Mass magnesium and oxygen yield magnesium oxide 2Mg + O2  2MgO

Sum Up : Physical or chemical? Bending a piece of wire Burning coal Cooking steak Cutting grass Corroding nail Dissolving sugar in coffee Fermenting a grape

Sum Up : Physical or chemical? The following is a description of an unknown substance. The substance is a silvery white, lustrous metal. Its density is 1.738g/cm3. The substance burns in air to produce an intense white light. It reacts with chlorine to give a brittle white solid. It can be pounded into thin sheets.

                           States of Matter A physical state of a substance is a physical property of that substance Handout                           

States of Matter Entropy = disorder As water changes from solid to liquid to gas, the particles are becoming more disordered and gaining entropy.

States of Matter What is the vocabulary associated with the phase changes between solid, liquids, and gases? How do phase changes occur? What is really happening to the particles of a substance during a phase change?

States of Matter Heating Curve for Water As heat is added, water changes state This is an endothermic process because heat is being added

States of Matter

States of Matter

States of Matter

States of Matter http://www.youtube.com/watch?v=f2XQ97XHjVw

Building Blocks of Matter

Matter anything that has mass and takes up space Everything is made up of matter

Pure Substance Matter that has uniform and definite composition Matter that cannot be separated physically Elements and compounds

Element pure substance that is made of only one kind of atom simplest form of matter that can exist under normal laboratory conditions

Element http://www.youtube.com/watch?v=d0zION8xjbM

Element The periodic table organizes the elements

Element

Atom An atom is the smallest unit of an element that maintains the properties of that element

Compound substance that is made from the atoms of 2 or more different elements that are chemically bonded, and it can be separated by chemical means

Compound

Compound

Compound Properties of a compound are usually quite different from their elemental components

Compound

Mixtures physical blend of 2 or more kinds of matter and each retains its own identity and properties in the mixture Easily separated physically

Mixtures Heterogeneous mixtures are not uniform in composition Homogenous mixtures are completely uniform in composition; the components are evenly distributed throughout

Pure Substance versus Mixtures

Separation of Mixtures Physical properties, filtration, distillation, magnetic properties, and solubility

Separation of Mixtures

Separation of Mixtures

Classification of Matter Flow Chart

Classification of Matter

Element, Compound, or Mixture?