mp3s essays

mp3s essays As we are approaching the 21st century communications is becoming a vital key in business and home computing. As a result we are constantly inventing new ways in order to make communications easier for the user to access in our daily lives. Therefore the information superhighway has sparred awareness in home technology or lack of home technology. The abbreviation MP3 stands for MPEG (Moving Picture Experts Group) layer 3, which is a standard format for storing compressed music. An MP3 file is an audio file that has been compressed (anywhere from 1/5th to 1/17th of its original size) without any noticeable loss in sound quality. That means a great sounding file, in a package small enough that it can be downloaded and/or stored on your PC (MP3 files can be identified by their file extension, .mp3.). The basic idea is that music digitized at CD quality has information that can be suppressed with little or no quality loss, as perceived by most people. Thanks to this and some mathematics, it is possible to compress a digitized track to about 8 percent of its original size, or a compression ratio of 12:1. This means that, while a regular music CD can contain about one hour of music (74 minutes, actually), a similar CD used to store mp3 files can contain almost 12 hours of music. MP3 is used particularly for music distribution over the Internet, but is also used for other purposes such as real-time digital audio transmissions over ISDN (used by reporters). How is it possible to do this you ask? Well, I won't get into the technical details, but basically the MP3 encoder removes the parts of the sound not audible to the human ear. This means that MP3 is a 'loss' type of compression (comparable to JPEG in the graphics area). This means that what comes out from your CD or Wave file is NOT the same thing that comes out of the MP3 that has been created from the CD/Wav. The sound data that has been lost will not be returned if the MP3 is...

Limiting Reactant Theoretical Yield (Worked Problem)

Limiting Reactant Theoretical Yield (Worked Problem) The limiting reactant of a reaction is the reactant that would run out first if all the reactants were to be reacted together. Once the limiting reactant is completely consumed, the reaction would cease to progress. The theoretic yield of a reaction is the amount of products produced when the limiting reactant runs out. This worked example chemistry problem shows how to determine the limiting reactant and calculate the theoretical yield of a chemical reaction. Limiting Reactant and Theoretical Yield Problem You are given the following reaction: 2 H2(g) O2(g) → 2 H2O(l) Calculate: a. the stoichiometric ratio of moles H2 to moles O2b. the actual moles H2 to moles O2 when 1.50 mol H2 is mixed with 1.00 mol O2c. the limiting reactant (H2 or O2) for the mixture in part (b)d. the theoretical yield, in moles, of H2O for the mixture in part (b) Solution a. The stoichiometric ratio is given by using the coefficients of the balanced equation. The coefficients are the numbers listed before each formula. This equation is already balanced, so refer to the tutorial on balancing equations if you need further help: 2 mol H2 / mol O2 b. The actual ratio refers to the number of moles actually provided for the reaction. This may or may not be the same as the stoichiometric ratio. In this case, it is different: 1.50 mol H2 / 1.00 mol O2 1.50 mol H2 / mol O2 c. Note that the actual ratio of smaller than the required or stoichiometric ratio, which means there is insufficient H2 to react with all of the O2 that has been provided. The insufficient component (H2) is the limiting reactant. Another way to put it is to say that O2 is in excess. When the reaction has proceeded to completion, all of the H2 will have been consumed, leaving some O2 and the product, H2O. d. Theoretical yield is based on the calculation using the amount of limiting reactant, 1.50 mol H2. Given that 2 mol H2 forms 2 mol H2O, we get: theoretical yield H2O 1.50 mol H2 x 2 mol H2O / 2 mol H2 theoretical yield H2O 1.50 mol H2O Note that the only requirement for performing this calculation is knowing the amount of the limiting reactant and the ratio of the amount of limiting reactant to the amount of product. Answers a. 2 mol H2 / mol O2b. 1.50 mol H2 / mol O2c. H2d. 1.50 mol H2O Tips for Working This Type of Problem The most important point to remember is that you are dealing with the molar ratio between the reactants and products. If you are given a value in grams, you need to convert it to moles. If youre asked to supply a number in grams, you convert back from the moles used in the calculation.The limiting reactant isnt automatically the one with the smallest number of moles. For example, say you have 1.0 moles of hydrogen and 0.9 moles of oxygen in the reaction to make water. If you didnt look at the stoichiometric ratio between the reactants, you might choose oxygen as the limiting reactant, yet hydrogen and oxygen react in a 2:1 ratio, so youd actually expend the hydrogen much sooner than youd use up the oxygen.When youre asked to give quantities, watch the number of significant figures. They always matter in chemistry!