Liquid is a state of matter in which molecules are in

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Liquid is a state of matter in which molecules are in contact with one another but are not rigidly held in place. Liquid also occupies specific volume, but its fluidity causes it to take the shape of the contained in which it is residing. Gas(vapor) is a state of matter in which the attractive forces between molecules are small enough to permit them to move with complete freedom. A gas has neither a definite shape nor volume, and it will completely fill any contained into which it is placed. At a high enough temperature (100 degrees Celsius) water boils and rapidly changes into steam. Similarly, at 0 degrees Celsius, water solidifies or freezes into ice. Under certain, conditions, some solids can be converted directly into a gaseous state. Sublimation is a physical change from the solid state directly into the gaseous state. No new chemical species are formed; matter is simply being changed from one physical state to another. Water, whether in the form of liquid, ice, or steam remains chemically H20. Simply, what has been altered are the attractive forces between the water molecules. - In a solid, these forces are very strong, and the molecules are held closely together in a rigid state. - In a liquid, the attractive forces are not as strong, and the molecules have more mobility. - In the vapor state, appreciable attractive forces no longer exist among the molecules; thus, they may move in any direction at will. Phase is a uniform body of matter; different phases are separated by definite visible boundaries. - Whenever substances can be distinguished by a visible boundary, different phases are said to exist Several of the most important of these for the forensic characterization of glass is density and refractive index
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Basic Units of Measurements The metric system has basic units of measurement for length, mass and volume: the meter, gram, and liter, respectively. The three basic units can be converted into subunits that are decimal multiples of the basic unit by simply attaching a prefix to the unit name. PREFIX EQUIVALENT VALUE DECI- 1/10or 0.1 CENTI- 1/100 or 0.01 MILLI- 1/1000 or 0.01 MICRO- 1/1,000,000 or 0.000001 NANO- 1/1,000,000,000 or 0.000000001 KILO- 1,000 MEGA- 1,000,000 One interesting aspect of the metric system is that volume can be defined in terms of length. A liter by definition is the volume of a cube with side of length 10 centimeters. It may be necessary to convert units from the metric system into the English system, or vice versa. - 1 inch = 2.54 centimeters - 1 meter = 39.37 inches - 1 pound = 453.6 grams - 1 liter = 1.06 quarts - 1 kilogram = 2.2 pounds Example: By converting 12 inches into centimeters (2.54 centimeters per inch). Multiply 12 inches by 2.54 centimeters per inch, the unit of inches will cancel out, leaving the product 30.48 cm. Density Density is a physical property of matter that is equivalent to the mass per unit volume of a substance (Density = mass/volume) Intensive property is a property that is not dependent on the size of an object - Solids tend to be denser than liquids - Liquids are denser than gases Determining Density of solid: - First the solid is weighed on a balance against known standard
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  • Fall '19
  • Light, Wavelength, refractive index

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