Question

A sample of oxygen at 29°C occupies 478 mL.If this sample later occupies 1132 mL at 62°Cand 1.7 atm, what was its original pressure?Answer in units ofatm.

Answer 1

To solve this problem we can use the Ideal gas law:

$\frac{P_1\cdot V_1}{T_1}=\frac{P_2\cdot V_2}{T_2}$

We deduce from the text:

V1=478mL

T1=29°C=302.15K

V2=1132mL

T2=62°C=335.15K

P2=1.7atm

Then we just have to solve for P1 and use the provided data:

$P_1=\frac{P_2\cdot V_2}{T_2\cdot V_1}\cdot T_1=\frac{1.7atm\cdot1132mL}{335.15K\cdot478mL}\cdot302.15k=3.63atm$

The initial pressure was P1= 3.63atm