In chemistry, the acidity of a liquid is commonly measured in pH. pH is important outside of chemistry to many things, including keeping swimming pools maintained, and measuring the acidity of rain. The pH scale is related to the concentration of hydrogen ions in the liquid, a number that tends to be very small, so the pH scale was introduced to make the numbers easier to work with. For a given concentration of hydrogen ions, H, measured in Molars, the pH is determined by pH = -log(H) Purified tap water has a hydrogen ion concentration of 10-7 M. Find the pH of water.