Trimix is a gas mixture consisting of oxygen, helium, and nitrogen used for deep scuba dives. The helium is included to reduce the effects of nitrogen narcosis and oxygen toxicity that occur when too much nitrogen and oxygen dissolve in the blood. A tank of Trimix has a total pressure of 200 atm, and the partial pressure of He is 34 atm. What is the percent by volume of He in the tank? (LO 10.7) (a) 17% (b) 38% (c) 23% (d) 83%