Today we learned about Water, which is the most important resources of Earth. In chemistry, H2O also known as Water which consisting 3 atoms. Oxygen atoms form a covalent bond with hydrogen atoms. We know that oxygen has a greater electronegativity than hydrogen. So that oxygen creates partial negative charges and hydrogen creates partial positive charge. Surface tension is the inward force pull to tend the aruface area of liquid. Molar mass of water is 18g/mol but boiling point is 100 degree celcius. Hydrogen bonding gives high surface tension, low vapor pressure, and high boiling point.