If the final mass of the system is 120g, what was the percent yield of the reaction?

Which of the following is always a reactant in a combustion reaction? oxygen nitrogen hydrogen carbon

Me i dont know what to do! the table compares the number of electrons in two unknown neutral atoms. comparison of electrons atom number of electrons a 10 d 11 use this information to determine the number of valence electrons in the atoms. which of the following correctly compares the stability of the two atoms? both are unreactive. both are highly reactive. a is unreactive and d is reactive. a is reactive and d is unreactive.

The number to the right of an element's symbol (ex. c-12) identifies the of an isotope.