What is the average atomic mass of einsteinium? what are its common isotopes?

In a laboratory, 1.55mg of an organic compound containing carbon, hydrogen, and oxygen is burned for analysis. this combustion resulted in the formation of 1.45mg of carbon dioxide and .89 mg of water. what is the empirical formula for this compound?

Which terms are used to identify pure substances

Draw a line graph showing the relationship between temperature in kelvin as a function of kinetic energy.