A sample of 25 L of #NH_3# gas at 10°C is heated at constant pressure until it fills a volume of 50 L. What is the new temperature in °C?

1 Answer
Aug 9, 2017

#293# #""^"o""C"#

Explanation:

We're asked to find the new temperature of the #"NH"_3# after it is subdued to a change in volume (with constant pressure).

To do this, we can use the temperature-volume relationship of gases, illustrated by Charles's law:

#ulbar(|stackrel(" ")(" "(V_1)/(T_1) = (V_2)/(T_2)" ")|)# #" "#(constant pressure and quantity of gas)

where

  • #V_1# and #V_2# are the initial and final volumes of the gas

  • #T_1# and #T_2# are the initial and final absolute temperatures of the gas (which must be in Kelvin)

We have:

  • #V_1 = 25# #"L"#

  • #V_2 = 50# #"L"#

  • #T_1 = 10# #""^"o""C" +273 = ul(283color(white)(l)"K"#

  • #T_2 = ?#

Let's rearrange the above equation to solve for the final temperature, #T_2#:

#T_2 = (V_2T_1)/(V_1)#

Plugging in known values:

#T_2 = ((50cancel("L"))(283color(white)(l)"K"))/(25cancel("L")) = color(red)(ul(566color(white)(l)"K"#

You asked for the temperature in degrees Celsius, so we convert back:

#color(red)(566color(white)(l)"K") - 273 = color(blue)(ulbar(|stackrel(" ")(" "293color(white)(l)""^"o""C"" ")|)#