Part 14 of Chapter 1 in Chemistry

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I gave the rest of the Chapter pictures to follow but Grandma must break them down for those impaired. Therefore, it may take a few more lessons. This lesson starts Temperature Measurements. " The most commonly used temperature scale in scientific work is the 'Celsius' scale. It gets its name from the Swedish astronomer Anders Celsius and dates back to 1742. For a long time, it was called the centigrade scale because it is based on the concept of dividing the distance on a thermometer between the freezing point of water and its boiling point into 100 equal markings or degrees. Another scale used by the SI system is based on the lowest theoretical temperature (called absolute zero) This temperature has never actually been reached, but scientists in laboratories have recorded temperatures within about a billionth of a unit above absolute zero. William Thomson, also known as Lord Kelvin, proposed this scale. A unit (the kelvin) is the same size as a Celsius degree and is referred to as the 'Kelvin' or absolute temperature scale. Through experiments and calculations, it has been determined that absolute zero is 273.15 degree below zero on the Celsius scale. This figure is usually rounded off to -273-degree C. A note here: The kelvin has no degree sign associated with it. Following diagram and formulas give the graphic and algebraic relationships between the temperature scales encountered in chemistry. Using the diagram on the next page of three thermometers. One marked Celsius, with the boiling as 100 degree and a freezing point of 0 degree. Another thermometer is marked as Fahrenheit with a boiling point of 212 degree and freezing point of water of 32 degree, and another thermometer marked with the Kelvin boiling point of water at 373 and the freezing point of water at 273. Then the Conversion Formulas of the degree of F=9/5C+32 degree; the degree of C=5/9(F-32degree); K=the degree of C + 273degree; the degree of C=K-273. Example 1- 30degreeC=? F, Solution: degree F=9/5(30degree) + 32 degree =86degree; Example 2-68degreeF=? degree C, Solution: degree C=5/9(68degree-32degree)=20degree; Example 3-10degree C=?K, Solution: K=10+273=283K; Example 4-200K=?degree C, Solution: degree C=200-273=-73degree