Final answer:
The temperature of the helium gas is approximately 925 K.
Step-by-step explanation:
To determine the temperature of the helium gas, we can use the ideal gas law equation: PV = nRT, where P is the pressure, V is the volume, n is the number of moles, R is the ideal gas constant, and T is the temperature in Kelvin. Rearranging the equation to solve for temperature, we have T = PV/nR.
First, we need to convert the mass of helium to moles using the molar mass of helium. The molar mass of helium is 4 g/mol. So, for 4.45 g of helium, the number of moles can be calculated as (4.45 g)/(4 g/mol) = 1.1125 mol.
Substituting the given values into the equation, we have T = (2.10 atm)(19.7 L)/(1.1125 mol)(0.0821 L*atm/(mol*K)). Evaluating this expression, the temperature of the helium gas is approximately 925 K.