STP condition mean we have P=1 atm. T=273K. R=ideal gas constant, but make sure you use the one that has the same units of pressure, temperature that you are using. In this case R=0.0821 L*atm K^-1mol^1. You are provided with n=2.1 moles.
V=nRTP
Input your values and solve.
The correct scientific notation is 7.82 x 105 g
The objects mass I took physical science
Explanation:
option option B is the correct answer of given statement helium-4(He)=2