Question #46508
1 Answer
Explanation:
We're asked to find the original pressure of the gas, given its initial and final temperatures, and the final pressure.
To do this, we can use the GayLussac's law equation:
#(P_1)/(T_1) = (P_2)/(T_2)#
where

#P_1# is the original pressure (what we're trying to find) 
#T_1# is the original absolute temperature, which must be in Kelvin:
#150# #""^"o""C"# #+ 273 = ul(423color(white)(l)"K"#

#P_2# is the final pressure (#456# #torr"# ) 
#T_2# is the final temperature, which is
#75.0# #""^"o""C"# #+ 273 = ul(348color(white)(l)"K"#
Let's rearrange the equation to solve for the unknown,
#P_1 = (T_1P_2)/(T_2)#
Plugging in known values, we have
#P_1 = ((423cancel("K"))(456color(white)(l)"torr"))/(348cancel("K")) = color(red)(ulbar(stackrel(" ")(" "554color(white)(l)"torr"" "))#