Is it possible to identify something as an element, compound or pure substance

E Coal and petrol are called non-renewable sources of energy, why

The prefix used for 100 times the base unit is

How to calculate molar mass

Lichens are an example of a (n)

When heated, lithium reacts with nitrogen to form lithium nitride: 6Li (s) + N2 (g) → 2Li3N (s) What is the theoretical yield of Li3N in grams when 12.7 g of Li is heated with 34.7 g of N2? g If the actual yield of Li3N is 5.

Is phosphorous an atom, element, or compound

A noble gas consists of three isotopes of masses of 19.99 amu, 20.99 amu, and 21.99 amu. the relative abundances of these isotopes are 90.92%, 0.257%, and 8.82% respectively. what is the average atomic mass of this noble gas? what noble gas is this?

Adding iron filings to sand

Which of the following sets of empirícal formula, molar mass, and molecular formula is correct?

Hexane and hexene are hydrocarbon compounds from different homologous series. the combustion of these two compounds produce different amount of soot. explain the difference based on the percentage of carbon by mass.