CHARLES' LAW
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Charles's law (also known as the law of volumes) is an experimental gas law which describes how gases tend to expand when heated.
A modern statement of Charles' law is: At constant pressure, the volume of a given mass of an ideal gas increases or decreases by the same factor as its temperature on the absolute temperature scale (i.e. the gas expands as the temperature increases).[1] which can be written as: VαT where V is the volume of the gas; and T is the absolute temperature. The law can also be usefully expressed as follows: V1 T2 = V2 T1 The equation shows that, as absolute temperature increases, the volume of the gas also increases in proportion. Charles' Law describes the direct relationship of temperature and volume of a gas. Assuming that pressure does not change, a doubling in absolute temperature of a gas causes a doubling of the volume of that gas. A drop of absolute temperature sees a proportional drop in volume. The volume of a gas increases by 1/273 of its volume at 0°C for every degree Celsius that the temperature rises. Charles' Law must be used with the Kelvin temperature scale. This scale is an absolute temperature scale. At 0 K, there is no kinetic energy (Absolute Zero). According to Charles' Law, there would also be no volume at that temperature. This condition cannot be fulfilled because all known gases will liquify or solidify before reaching 0 K. The Kelvin temperature scale is Celcius minus 273.15 °. Therefore, zero Kelvin would be -273.15 ° and any Celcius temperature can be converted by to Kelvin by adding 273.15 (273 is often used). Any unit of volume will work with Charles' Law, but the most common are liters (dm3) and milliliters (cm3). |
Check out this video and answer the problems below.1) A container holds 50.0 mL of nitrogen at 25° C and a pressure of 736 mm Hg. What will be its volume if the temperature increases by 35° C?
2. ) A sample of oxygen occupies a volume of 160 dm3 at 91° C. What will be volume of oxygen when the temperature drops to 0.00° C? 3) A sample of hydrogen has an initial temperature of 50.° C. When the temperature is lowered to -5.0° C, the volume of hydrogen becomes 212 cm3. What was the initial volume of the hydrogen in dm3? 4) 568 cm3 of chlorine at 25° C will occupy what volume at -25° C while the pressure remains constant? 5) A sample of helium has a volume of 521 dm3 at a pressure of 75 cm Hg and a temperature of 18° C. When the temperature is increased to 23° C, what is the volume of the helium? |