Examples of index fossils. Index fossils (also known as guide fossils, indicator fossils or zone fossils) are fossils used to define and identify geologic periods (or faunal stages).
Methyl cellulose. Methyl cellulose (or methylcellulose) is a chemical compound derived from cellulose. It is a hydrophilic white powder in pure form and dissolves in cold (but not in hot) water, forming a clear viscous solution or gel.
CaF does not exist .Its CaF2. Though CaF2 is an ionic compound ,it is almost insoluble in water. But it is very slightly soluble in water. Its solubility is 0.0015g/100 ml at 25 degree centigrade .Which is very low amount.So its considered insoluble. C2H5OH, ethanol, is considered soluble in water due to miscibility of ethanol .Miscibility is a term that refers to the property of liquids to mix in all proportions, forming a homogeneous solution.ut its solubility is 0.8 g/100 ml at 25 degrees c which is also very low NH3, ammonia, is soluble in water due to the formation of NH4+ and OH-with water .Its solubility is 89.9 g/100 ml (0 Â°C). Source(s): See solubility in water in www.wikipedia.org for reference.