Lecture 1: Phases and Classification of Matter

LECTURE 1 : Phases and Classification of Matter Substance is characterized as anything that occupies space and has mass, and it's all around us. Solids and liquids are more obviously substance: We can observe that they take up space, and their weight informs us that they have mass. Vapors are also substance; if vapors didn't take up space, a balloon would remain collapsed instead of inflating when filled with gas. Solids, liquids, and vapors are the three phases of substance generally found on earth . A solid is inflexible and possesses a definite shape. A liquid flows and takes the shape of a container, except that it forms a flat or slightly curved top when acted upon by gravity. (In zero gravity, liquids assume a spherical shape.) Both liquid and solid samples have volumes that are very nearly independent of pressure. A vapor takes both the shape and volume of its container. A fourth state of matter, plasma, naturally appears in the interiors of stars. A plasma is a gaseous state of matter that includes significant numbers of electrically charged particles , The presence of these charged particles gives unique properties to plasmas that warrant their classification as a state of matter different from gases. As well as stars, plasmas are found in a few other high-temperature environments (both natural and human-made), like lightning strikes, some television screens, and specialized analytical instruments utilized to detect trace amounts of Metals. Some samples of substance seem to have characteristics of solids, liquids, and/or gases simultaneously. This can occur when the sample is comprised of many small parts. For instance, we can pour sand as though it were a liquid since it is composed of many small grains of solid sand. Matter can also possess properties of more than one state when it is a mixture, such as with clouds. Clouds seem to behave somewhat like gases, but they are actually mixtures of air (gas) and small particles of water (liquid or solid). The mass of an object is a measurement of the amount of matter within it. One method to measure an object’s mass is to measure the force it takes to accelerate the object. It takes far more force to accelerate a car than a bicycle because the car has much greater mass. A more common approach to ascertain the mass of an object is to utilize a balance to compare its mass with a standard mass. Even though weight is associated with mass, it's not the same thing. Weight pertains to the force that gravity imposes on an object. This force is directly proportional to the mass of the object. The weight of an object varies as the force of gravity varies, but its mass does not. An astronaut’s mass does not alter simply because she goes to the moon. But her weight on the moon is merely one-sixth her earth-based weight because the moon’s gravity is only one-sixth that of the earth’s. She may feel “weightless” during her trip when she undergoes negligible external forces (gravitational or any other), even though she is, of course, never “massless.” The law of conservation of matter encapsulates many scientific observations about matter: It asserts that there is no detectable change in the overall quantity of substance present when matter converts from one form to another (a chemical into ethanol and carbon dioxide, and the overall mass of the materials doesn't alter. This is also visible in a lead-acid vehicle battery: The initial substances (lead, lead oxide, and sulfuric acid), which are able to generate electricity, become other substances (lead sulfate and water) that don't make electricity, with no variation in the genuine quantity of matter change) or transforms among solid, liquid, or gaseous states (a physical change). Brewing beer and the operation of batteries offer examples of the conservation of matter .Throughout the brewing of beer, the ingredients (water, yeast, grains, malt, hops, and sugar) are transformed into beer (water, alcohol, carbonation, and flavoring substances) with no actual loss of substance. This is most clearly observed during the bottling process, when glucose converts While this conservation principle is accurate for all transformations of substance, persuasive illustrations are uncommon because, beyond the regulated environments in a lab, we rarely gather all the material generated throughout a specific transformation. As an illustration, when you consume, digest, and absorb food, all the matter in the initial food is retained. However, because some of the substance is integrated into your body, and much is discharged as different forms of waste, it's difficult to confirm by measurement.