Question

a sample measures 2.00 L of stp. calculate in Cif the volume changes to 1.00 L and the pressure is changed to .500 atm

Answer 1

do you mean in CC (Cubic Centimeter)
and i s the temperature constant

assuming temperature to be constant....
\[P _{1} V _{1}=P _{2} V _{2}\]
THEREFORE...\[X*2=.500*1\]
X=0.25 L

(1 LITER=1000CC)

FINAL VOLUME IS 250CC

Answer 2

I think she means C as in new temp, since BOTH the volume and pressure changes are given. In this case, you should use the combined gas law:\[\frac{P_1V_1}{T_1} = \frac{P_2V_2}{T_2}\]and solve for the new temp.