Not sure which gas law to use, here's the question.

A quantity of potassium chlorate is selected to yield, through heating, 75.0 ml of O^2 when measured at STP. If the actual temperature is 28 C and the actual pressure is 0.894 atm, what volume of oxygen will result?

I was thinking about combined gas law, but I can't since I don't have a second pressure and temperature. I only have 1 volume, 1 temperature, and 1 pressure.

Question

Not sure which gas law to use, here's the question.

A quantity of potassium chlorate is selected to yield, through heating, 75.0 ml of O^2 when measured at STP. If the actual temperature is 28 C and the actual pressure is 0.894 atm, what volume of oxygen will result?

I was thinking about combined gas law, but I can't since I don't have a second pressure and temperature. I only have 1 volume, 1 temperature, and 1 pressure.

ookawaiioo · Answer

You are measuring at STP = Pressure is at 1 atm, and temperature is at 273.15 K. 

So you have P1, T1, and V1 (0.075 L).

You are given temperature is 28 C (301.15 K, or T2)  and the actual pressure is 0.894 atm (P2)

By using the ideal gas law......

$$\frac{ P1V1 }{ T1 } =\frac{ P2V2 }{ T2}$$

Solve for V2

anonymous · Answer

Oh I see, I am going to try that. Brb

anonymous · Answer

I got 92.5 ml, which I think is right. Thanks! I forgot all about STP