You have a balloon filled with hydrogen gas
which keeps it at a constant pressure,
regardless of its volume. The initial volume of
the gas is 736 mL at 15.0°C. The gas is heated
until its volume is 2.28 L, what is its final
temperature in degrees Celsius?

619.2 K

Explanation:

We can solve this problem by using Charle's Law, which states that:

"For a fixed mass of an ideal gas kept at constant pressure, the volume of the gas is directly proportional to its absolute temperature"

Mathematically:

where

V is the volume of the gas

T is the absolute temperature

The equation can be rewritten as follows for a gas that undergoes a transformation at constant pressure:

where in this problem:

is the initial volume of the gas

is the initial temperature

is the final volume of the gas

Solving for T2, we find the final temperature:

Converting into Celsius degrees,