What is the enthalpy of combustion of C3H8 in the reaction shown above? If you are planning on answering with a link to a file please don’t answer. I need a real answer with an explanation. Please and thank you

Plz choose one of the compounds from the table and explain how you know the numbers of atoms in your formula. is it possible for two different compounds to be made from the exact same two elements? why or why not? with a limited number of elements (less than 120 are known), does this mean we also have a small number of compounds or do we have a large number of compounds in this world?

Calculate the molar mass of aluminum oxide (al2o3). express your answer to four significant figures.

Estimate the molar mass of the gas that effuses at 1.6 times the effusion rate of carbon dioxide.