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Chemistry Unit Seven

Chemistry Unit Seven. Matter and Energy. Matter. Matter anything that has a mass and takes up space. Law of Conservation of Mass/Matter Matter cannot be created or destroyed in an ordinary chemical reaction just rearranged to form different substances

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Chemistry Unit Seven

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  1. Chemistry Unit Seven Matter and Energy

  2. Matter • Matter • anything that has a mass and takes up space. • Law of Conservation of Mass/Matter • Matter cannot be created or destroyed in an ordinary chemical reaction just rearranged to form different substances • Matter can be described using properties..

  3. PROPERTIES CHEMICAL PHYSICAL EXTENSIVE INTENSIVE Types of Properties

  4. Characteristics of Matter • Physical Properties • Characteristics of a substance that can be observed without the production of a new substance. • Examples: • Color,smell, taste, hardness, density, texture, melting/boiling/freezing points, magnetic attraction, solubility, electrical conductivity, temperature, state or phase

  5. Two Types of Physical Properties • Extensive • Depends on the particular sample • examples: volume, mass, weight, shape, etc… • Intensive • Depends on the type of matter  NOT size of sample • examples: color, melting point, specific heat, density, appearance, etc…

  6. Characteristics of Matter • Chemical Properties • describes how a substance reacts or fails to react with other substances to produce new substances. • Examples: • Oxidation, Corrosion, Hydrolysis, Combustion, Flammability, Reaction to Acid or Base.

  7. Two Types of Changes • Physical Change • an alteration of a substance that only changes the physical properties of the substance. • Does not change the chemical composition of the matter!!

  8. Characteristics of Matter • Chemical Change • an alteration of the chemical composition of a substance that results in the formation of a new substance • ALWAYS forms a new substance that has different physical and chemical properties than the original substance. • Also known as a chemical reaction.

  9. Kinetic Theory • All matter is made of tiny particles in constant motion. • Potential Energy (PE) • energy due to the position or condition • at the atomic level: • the distance between the particles • closer= lower PE farther = higher PE • Kinetic Energy (KE) • energy due to motion • Faster=higher KE slower= lower KE

  10. Based upon particle arrangement • Based upon energy of particles • Based upon distance between particles • AKA POTENTIAL AND KINETIC

  11. SOLIDS • Particles are tightly packed, vibrating about a fixed position • definite shape • definite volume Heat

  12. LIQUID • Particles are tightly packed, but are far enough apart to slide over one another • indefinite shape • a definite volume Heat

  13. GAS • Particles are very far apart and move freely • indefinite shape • indefinite volume Heat

  14. Phases of Matter Arranged in orderly pattern Yes Yes Touching, but not tightly packed No Yes Far apart and rarely touching No No

  15. Phases of Matter Vibrational only Low Ice Very Low Vibrational & translational Low Moderate Water High High Vapor Move freely

  16. Plasma • extraordinary state of matter • consists of high energy particles • electrons are stripped from their nuclei • examples: • fluorescent light • Stars • Lightning *Most Abundant State of Matter in the Universe!*

  17. STATES OF MATTER LIQUID PLASMA SOLID GAS Tightly packed, in a regular pattern Vibrate, but do not move from place to place Close together with no regular arrangement. Vibrate, move about, and slide past each other Well separated with no regular arrangement. Vibrate and move freely at high speeds Has no definite volume or shape and is composed of electrical charged particles

  18. http://www.harcourtschool.com/activity/states_of_matter/ ANIMATION

  19. Phase Changes Changes of State Adding or removing energy (heat) to a substance causes phase changes The potential energy of the particles is increased or decreased During a phase change, temperature does NOT change

  20. Phase Changes • Melting • S Δ L (adding energy) • Freezing • L Δ S (removing energy) • Melting point & freezing point of a substance occur at the same temperature.

  21. Phase Changes • Boiling • L Δ G (adding energy) • Evaporation • L Δ G (adding energy) • Condensation • G Δ L (removing energy) • Difference between boiling & evaporation: • Boilinga specific temp. below the surface • Evaporation any temp. at the surface

  22. Phase Changes • Deposition • G Δ S (removing energy) • Examples: Snow, frost • Sublimation • S Δ G (adding energy) • Examples: solid CO2 (dry ice), solid air fresheners

  23. Phase Change Graphs (T vs t) Liquid Melting Solid AB -heat Δ KE -move faster -temp.  -solid BC -heat Δ PE -get farther apart -temp. stay same -melting CD -heat Δ KE -move faster -temp.  -liquid

  24. Phase Change Graph (T vs t) Gas Boiling DE -heat Δ PE -get farther apart -temp. stay same -boiling EF -heat Δ KE -move faster -temp.  -gas

  25. Phase Change Graph (T vs t) A C B E D F CD -KE  -slows down -temp.  -Liquid AB -KE  -slows down -temp.  -Gas BC -PE  -closer together -temp. stays same -Condensation

  26. Phase Change Graph (T vs t) A B C D E F DE -PE  -closer together -temp. stays same -Freezing EF -KE  -slows down -temp.  -Solid

  27. Phase Change Graph (T vs t) Boiling Point Boiling Freezing Point & Freezing Melting Point Melting What is the boiling point? What is the melting point? What is the freezing point?

  28. Phase Change Graph (T vs t) If melting & freezing points occur at the same temperature, how do you know which change is occurring? -depends on whether adding or removing energy

  29. Phase Change Graph (T vs t) What is this substance? -Water How do you know? -Boiling & melting & freezing points of water (Intensive properties)

  30. Energy and Chemical Reactions • When a chemical reaction occurs, bonds are formed and bonds are broken. • If the energy required to form the new bonds is greater than the energy of the original bonds, the reaction requires the addition of energy and is called: Endothermic. • During an endothermic reaction, the temperature decreases. (Heat taken in is changed into bond energy.)

  31. Energy and Chemical Reactions • If the energy required to form the new bonds is less than the energy of the original bonds, the reaction gives off energy and is called: Exothermic. • During an exothermic reaction, the temperature increases. (Bond energy is released in the form of heat.)

  32. Classification of Matter Matter Pure Substances Mixtures Elements Compounds Homogeneous Heterogeneous Solution Colloid Suspension

  33. Matter • Pure Substances • made of only one type of matter • Mixtures • a physical combination of two or more substances • no definite ratio of particles • Element • made of only one type of atom • cannot be broken down into simpler substances under normal laboratory conditions

  34. Matter (cont’d) • Compound • Atoms of two or more elements, chemically combined in a definite ratio. • Homogeneous Mixtures • Two or more substances, physically combined in no definite ratio. • The same throughout. • Must be a SOLUTION • Heterogeneous Mixture • Two or more substances, physically combined in no definite ratio. • Different throughout

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