1. The problem statement, all variables and given/known data If a person breathes 10 liters per minute of air at 68 degrees F and 50% relative humidity, how much water per day must the internal membranes supply to saturate the air at 98.6 degrees F? (Assume all the moisture is exhaled). I f each gram of water extracts 580 calories as it is vaporized, how much daily heat loss in kilocalories (food calories) does this represent? 2. Relevant equations 3. The attempt at a solution My instructor provided us that saturation vapor pressure at 20 degrees C is 17.3 g/m cubed and at 37 degrees C is 44.0 g/m cubed. I believe I should be able to figure out the calorie portion of the problem by using a formula from my book but I am unsure about the relative humidity part. Unless I am just over looking the information that is there. Would I need to find the number of g/m^3 for the 10 liters to start? I'm just not quite sure. Thanks in advance for any help.