[tÃ¤râ²sÉs] pl. tarsi. Etymology: Gk, tarsos, flat surface. 1 the flat area of articulation between the foot and the leg or the edge of the eyelid. 2 also called tarsal cartilage, tarsal plate. Any one of the fibrous plates of cartilage about 2.5 cm long that form the eyelids. One tarsal plate shapes and gives solidarity to the edge of each eyelid.
Hydrogen is reduced by elements that are less electronegative to form compounds in which its oxidation number is -1. Properties and Formation of Hydrogen. At room temperature, hydrogen is a colorless, odorless gas with a density only one-fourteenth the density of air. Small quantities of H 2 gas can be prepared in several ways. 1.
So any gas with a MW less than 29 will be lighter than air. That, by the way, includes nitrogen! Methane has a MW of 16; helium is 4; hydrogen is 2. I can't think of any other compound or element that's a gas at STP that has a MW less than 29. Afterthought: OK, neon has a molecular weight of 20, which is lighter than air. Ammonia (gas at room temp) has a MW of 17.