Cheatography

# 7th Grade Physics and Chemistry Cheat Sheet by [deleted]

Physics and Chemistry Foundation

### Matter

 Matter Has Mass; Occupies Space Classi­fic­ation by States Solid; Liquid; Gaseous Behaviour Inter-­mol­ecular Forces (Attra­ction & Repuls­ion); Shape; Volume; Matter is classified by its behaviour at the given time. Classi­fic­ation by Purity pure: Substance; impure: Mixture Aliases Substance Substance Element; Compound Element Simplest substance; Chemical reactions cannot break them down further into other substa­nces; Smallest particle: Atom Compound Smallest particle: Molecule; Consists of multiple Elements Charac­ter­istic Property indepe­ndent of Shape, and Size Physical Property Value can be known without altering the substance. Chemical Property Value cannot be determined without altering the substance. Mass Amount of matter in the object. Volume Amount of space occupied by an object. Density Mass per unit volume.

### Temper­ature & Heat

 Heat Excites the Molecules; Causes matter to Expand; Reduces its Density; Changes State of Matter. Kinetic Energy Anything that is in motion has Kinetic Energy. Temper­ature It is a measure of the average kinetic energy of the molecules. It isn’t exactly equal to the average kinetic energy, but is directly propor­tional to the average kinetic energy of the molecules in the substance. Temper­ature Units Kelvin, or Celsius (Centi­grade), or Fahren­heit; °F = °C x 9/5 + 32; °C = °K + 273 Thermal Energy Sum of kinetic and potential energies of all the particles in an object. Heat Revisited It is the energy "in transi­t"; Objects don’t “contain” heat, but rather transfer heat from one place to another; An object can “have” a certain amount of thermal energy, but an object cannot “have” heat. Absolute Zero Temper­ature All molecular motion ceases; Nothing could be colder than this; No heat energy remains in a substance; 0 K, or −273.15 °C, or −459.67 °F. Normal Body Temper­ature 98.6 °F, or 37 °C, or 310.15 K Latent Heat The heat that is absorbed (or released) without raising or reducing the temper­ature. Heat absorbed causes the molecular bonds to break, and thus causes the change of state of matter. Parts of Thermo­meter Glass Tube; Bulb; Kink Clinical Thermo­meter Substance: Mercury; Range: 35 °C to 42 °C; Laboratory Thermo­meter Substance: Alcohol; Range: -10 °C to 110 °C; Heat Transfer Conduc­tion; Convec­tion; Radiation Conduction Heat transfer between molecules by direct collision; From Hot to Cold. Convection Heat transfer by movement of masses; Density decreases with Heat. Radiation Heat transfer when objects are not touching; Hot object emits electr­oma­gnetic waves. Classi­fic­ation by heat conduc­tivity Good Conductors of Heat: Most Metals; Insula­tors: Air, Water, Wood, Plastic

### Electr­icity

Under temperature units the °K should be without the degree symbol. Is correct elsewhere on the cheatsheet.