PLEASE PLEASE HELP QUICK lots of points please Answer the following question:

Calculate the mass of 45.0 L of NH3 at 87.0° C and 750. mm Hg.

Use the Ideal Gas Law formula and here are values for R:

8.134 (L * kPa)/(mol * K)

0.0821 (atm * L)/(mol * K)

62.364 (L * mmHg)/(mol * K)

Include the following with your

Which Gas Law constant did you use or which "R" value did you use? Why?
The numerical answer to the question.
An explanation of the correct number of significant figures you will use for the numerical answer.