# A sample of gas occupies 17 mL at -112°C. What volume does the sample occupy at 70°C?

##### 1 Answer

Use Charles' Law, which states that at a constant pressure, temperature and volume are proportional.

It is also written as

#("V"_1)/("T"_1)=("V"_2)/("T"_2)#

Before we define our values, note that temperature in gas law equations always use Kelvin, not Celsius.

To go from degrees Celsius to Kelvin, add

Thus, we have

#"V"_1="17 mL"#

#"T"_1=-112^@"C"="161 K"#

#"V"_2=???#

#"T"_2=70^@"C"="343 K"#

Thus, we have

#("17 mL")/("161 K")="V"_2/("343 K")#

Cross-multiply to solve for

#17 * "343 mL" * "K"="161 K" * "V"_2#

#"5831 mL"="161 V"_2#

#color(red)("V"_2="36.2173913043 mL"#

The question technically has

This means the final answer is

#color(blue)("V"_2=4xx10^1# #color(blue)("mL"#