You will need to use the combined gas law in order to answer this question. The combined gas law is represented by the following equation: #"P"_1"V"_1"/T"_1"# = #"P"_2"V"_2"/T"_2"#. #"STP"# is #"273K"# and #"760.0 mmHg"#.
Given/Known :
#"P"_1# = #"760.0 mmHg"#
#"V"_1# = #"125 mL"#
#"T"_1# = #"273K"#
#"P"_2# = #"275 mmHg"#
#"V"_2# = #"425 mL"#
Unknown:
#"T"_2"#
Equation:
#"P"_1"V"_1"/T"_1"# = #"P"_2"V"_2"/T"_2"#
Solution: Rearrange the equation to isolate #"T"_2# on one side. Then solve for #"T"_2#.
#"T"_2# = #"P"_2"V"_2"T"_1"/P"_1"V"_1#
#"T"_2# = #"(275 mmHg)(425 mL)(273K)/(760.0 mmHg)(125 mL)"#
#"T"_2# = #"336K"#
Convert #"T"_2# from Kelvins to degrees Celsius .
#"336K - 273 = 63"^o"C"#