Answer:
The speed of molecules in a gas is directly proportional to the square root of the temperature and inversely proportional to the square root of the molar mass.
Since both gases are at the same temperature, we only need to compare their molar masses.
The molar mass of carbon dioxide (CO2) is 44 g/mol and the molar mass of hydrogen (H2) is 2 g/mol.
Therefore, the square root of the molar mass of hydrogen is smaller than the square root of the molar mass of carbon dioxide.
This means that the speed of hydrogen molecules is greater than the speed of carbon dioxide molecules at the same temperature.