Why do fossil fuels such as crude oil contain varying amounts of nitrogen and sulfur? Pls help

What is avogadro’s number, and why is it useful

What is a metal replacement reaction

Use this information to determine the number of calends electrons in the atoms. which of the following correctly compares the stability of the two atoms? a) both are unreactive b) both are highly reactive c) a is unreactive and d is reactive d) a is reactive and d is unreactive