danny_boy

Temp of earth's surface drops 5 degrees C for every 1000m of elevation above the surface. If the ground temp is 15 degrees C and pressure is 760mmHg, at what elevation will the pressure be 380mmHg. Assume ideal gas behavior.

Im taking an engineering course to broaden my horizons, but feel lost here.

Ideal gas law is Pv=nRT, so I know I need a relationship between temp and pressure, and then relate that to distance (elevation).

I need to find what the temperature is, when the pressure decrease by 1/2, and am unsure if I merely need to substitute values into a known equation, or formulate a new relationship. Any advice would be appreciated.

Thanks,