Charles Law Essays - Temperature, State Functions,

Charles Law Introduction: One of the variables that affects the volume of a gas is the temperature of the gas and its surroundings. This volume-temperature relationship is quantified in Charles's law. The law states that as the temperature of a gas decreases, the volume of the gas decreases proportionately. An ideal gas at 273 K, for example would decrease in volume by 1/273 of its original volume for each Celsius degree the temperature decreases. If the temperature decreased sufficiently, the volume should decrease to zero. Real gases, however, liquefy and solidify long before this theoretical limit, called absolute zero, is reached. By using air as a sample of a real gas and limiting the temperature range, it is possible to estimate the temperature that would correspond to absolute zero. Materials Used: Apron Goggles Thermometer Hot Plate Paper Towel Thin Stem Pipet (2) 400-mL Beakers Objectives: Demonstrate the relationships between the temperature of a gas and its volume. Graph the relationship. Estimate the temperature of absolute zero by extrapolation. Procedure: Fill two 400-mL beakers half full with tap water. Begin heating the water in one beaker to a temperature that is 10*C above room temperature. Fill a thin stem pipet completely with room temperature water. To make sure the pipet is filled, first draw in as much water as possible. Then, holding the pipet by the bulb with the stem pointing upward, squeeze the bulb slightly to eject any air left in the bulb and stem. Keeping this pressure on the bulb, insert the tip of the stem into the water. Release the pressure on the bulb, and the pipet will fill completely. Dispense the water from the pipet counting the total number of drops it takes to empty the pipet. Record the room temperature and the number of drops. Stop heating the water when a temperature 10*C above the room temperature is reached. Holding the thin stem pipet by the stem, immerse the bulb in the warm water. Hold the pipet in the warm water for a few minutes so that the air in the pipet reaches the temperature of the water. Pinch the stem of the pipet to seal off the bulb. Place the bulb in the other beaker of water which is at room temperature. Still pinching the stem, immerse the entire pipet, including the stem, in the water, release the stem underwater. A small amount of water should be drawn into the pipet. This water is equal in volume to the amount of gas lost when the pipet bulb was heated and the air inside it expanded. Remove the pipet from the water bath. Dry the outside of the pipet, with the paper towel. Expel the water, counting the number of drops of water that were drawn into the pipet. Add the number of drops to the initial volume noted. Record the total volume and the temperature of the warm water bath. Dry the inside of the pipet, by drawing in the air and then releasing the bulb several times. Repeat from the 6th to the 13th step at a temperature that is 10*C above the previous trial. Continue this procedure until the water temperature is approximately 75*C. Record all results. Data And Observations: Temperature/Volume Changes Of Air Temperature (*C) Total Volume (Drops) 19 134 29 138 39 140 49 160 59 169 69 178 Conclusions: 1- 2- 3- Errors And Possible Improvements: Possible errors could occur while counting the drops, people can either lose count, or too many drops will be let out instead of single drops. To improve this patience and tolerance are a must, hurrying will only cause the person to re-start from the beginning. Errors could also occur while taking the temperature of the warm water, if the hot plate is turned off, the beaker will obviously cool down a few degrees and so this might affect the results. An idea to improve this would be setting the hot plate on a moderate heat so that the same heat temperature can be stable throughout the procedures. Errors could occur if the tip of the pipet is not pinched properly, this will result in the false number of drops getting drawn into it. To improve this one must make sure the whole tip is pinched and that there is no space for any air to enter or escape. Errors could occur if the

Learn How to Tell Time in Italian

Learn How to Tell Time in Italian The simplest way to inquire about the time in Italian is by using the verb essere: Che ore sono? Che ora à ¨? – What time is it? You can use the above sentences interchangeably when asking about the time, but when responding you will always use sono le unless you are talking about 1 p.m. in the 12 hour clock (à © luna) or mezzogiorno and mezzanotte: Sono le diciassette. – It is the 17th hour or 5 pm.È mezzogiorno. – Its noon. Be Polite But even better, if you want to be polite add an excuse me into the mix: Mi scusi, che ora à ¨? – Excuse me, what time is it?Mi scusi, che ore sono? – Excuse me, what time is it? The two questions have the same meaning and basic structure. The difference is that the first uses ora à ¨? (is it now?), while the second uses sono le? (is it?). Both uses are perfectly acceptable, but the first conveys a slightly greater sense of immediacy. Useful Vocabulary: Morning, Afternoon, Evening and Night To indicate a.m. add di mattina: Sono le 11 di mattina. – It’s 11 in the morning. To indicate afternoon add del pomeriggio (12 noon to 5 pm): Sono le 2 del pomeriggio. – It’s 2 in the afternoon. To indicate evening use di sera . This period of time changes with seasons but it usually sits between the afternoon and the late night, from 5 pm to 9 or 10 pm: Sono le sei di sera. – It’s 6 in the evening. To indicate night time use di notte (10 pm to early morning): Sono le 3 di notte. – It’s three in the morning. Must-Know Vocabulary Words Additionally, there are a number of important words and phrases to know in relation to telling time in Italian. Heres a brief list with their English equivalents: Una mezz’ora (A half hour):Mamma arriva tra mezzora. – Mom arrives in thirty minutes.Un quarto d’ora (A quarter of an hour):Ho bisogno di un quarto dora per farmi una doccia. – I need 15 minutes to take a shower.A volte (Sometimes):A volte mi prendo un caffà ¨. – Sometimes I buy myself a coffee.Due volte al giorno (Twice a day):Passeggio al cane due volte al giorno. – I walk the dog twice a day.Tutti i giorni (Every day):Io vado al gym tutti i giorni. – I go to the gym every day.Ogni tanto (From time to time):Ogni tanto visito la mia zia in Chicago. – From time to time I visit my aunt in Chicago.Mancano cinque minuti alle... (It’s five minutes to...)Mancano cinque minuti alle 3 pm. – Its five to 3 pm.A che ora chiude? (What time does it close?):A che ora chiude la piscina? – What time does the pool close?A che ora apre? (What time does it open?):A che ora apre il panificio? – What time does the baker y open?A che ora comincia? (What time does it start?):A che ora comincia il film? – What time does the movie start? Reminder Dont forget that the 24 hour clock usage is widespread in Italy and most parts of Europe. In short, 1 p.m. is expressed as 13:00, while 5:30 p.m. is 17:30. An appointment or invitation for 19:30 is meant for 7:30 p.m. But the 12 hour clock is well known and everyone will understand when you use it. Finally, the months, as well as the days of the week in Italian, will give you more vocabulary and broaden your skills in the language.

How are databases used in organisations Essay Example | Topics and Well Written Essays - 1500 words

How are databases used in organisations - Essay Example Another type of databases is distributed databases. These are databases which are scattered and stored over different systems on a network. Object-oriented databases use the concept of classes and subclasses to store and organize data. Databases usually do not exist in isolation but are part of database systems. A database system, besides the collection of records, provides a number of features such as searching for records, accessing them and updating them. Typically databases use the language SQL (Structured Query Language) to access the data and make changes to it. Popular database systems include Oracle, IBM’s DB2 and Microsoft Access. Databases play a vital and indispensible role in organizations today and are of great importance. One of the reasons for this is that they have replaced the old paper files and records. This makes the information become compact and is no longer scattered in paper files. Not only do paper files taka a lot of space, they are also vulnerable of being destroyed by fire etc. Besides saving in the space, the database provides an easier access to data. It allows the users to retrieve data in very little time and to update it easily. Data from a database can be retrieved and sorted in a number of ways depending on the requirements. Databases can provide the same information to a number of users at the same time. A large number of users can access the information and update it simultaneously. This is not possible with manual systems (SQLServer.com). Databases usually contain collection of data records of files related to a common subject or entity. Typically databases are part of information systems. These systems are used for a number of purposes. In a business organization, databases are used for storing information on finance, sales, customer records etc. Similarly, databases are immensely used in banking, healthcare and education industries. In this paper, we shall focus on the use of databases in