Stuck on this chemistry problem help please

Question

1. A sample of gas occupies 5.0L at a pressure of 3.0 atm and a temperature of 37.0 °C. What would be the volume of this gas at STP? (R= 0.0821atm l/mole K)

0.0 L

0.040 L

13.2 L

111 L

Answer 1

Although you can solve pV=nRT twice to get the answer, you can note that at standard pressure, 1 atm, would triple the volume.  Lowering the temperature from 310 to 273 would lower the volume by about 10 percent.  So 13.2 L looks like the likely answer.  

Answer 2

PV = nRT

Temp. must be converted to K; then you can solve for n. Once you have n, you can again use the ideal gas equation, this time to compute the new volume at STP. Remember, STP is usually 273 K, 1 atm.

Good luck.