Convert the temperature of 21.5 degrees to the Kelvin Scale

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?

Which formula can be used to calculate the molar mass of hydrogen peroxide

In the space, show a correct numerical setup for calculating the number of moles of co2 present in 11 grams of co2