Charles’s+Law

Charles’s Law: V1/T1 = V2/T2 Charles’s Law states that the volume of a given amount of an ideal gas is directly proportional to the temperature in Kelvin (provided that the amount of gas and the pressure remain fixed.) As temperature increases, so does the volume of the gas (and vice versa.) Problem: What will be the volume of a gas sample at 36 degrees C if its volume at -58 C is 3.42 L? Assume that pressure is constant. Alright, so the first thing that you need to do in solving any gas law problem is figure out which of the equations to use. This equation deals only with temperature and volume so you have to use Charles’s Law. (Although the equation does mention pressure, it states that pressure is constant meaning that it can be disregarded.) V1/T1 = V2/T2 V1 = initial volume T1 = initial temperature V2 = final volume T2 = final temperature

Next determine your givens and what you are solving for. In this equation, it is asking you to solve for volume (V2) at the given temperature of 36 C, which is T2. V1 and T1 are also given to you in the problem, -58 C and 3.42 L. When using any equation that deals with temperature you must always make sure that temperature is expressed in Kelvin. This is true for any of the gas laws: temperature must always be converted to Kelvin. The conversion from degrees Celsius to Kelvin is fairly simple. All you have to do is add 273 to the temperature in degrees to get it into Kelvin. 36 C + 273 = 309 K -58 C + 273 = 215 K  Now to solve the equation; substitute the variables in Charles’s Law with their values… V1/T1 = V2/T2 3.42 L/215 K = V2/309 K To isolate V2 and solve for volume, multiply both sides of the equation by 309 K and calculate your answer. 3.42 L/215 K * (309 K) = V2/309 K * (309 K)  V2 = 3.42 L/215 K * (309 K)  Now, just calculate the value for V2. V2 = 4.92 L The equation is solved! :]



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