86.4g of KBr is dissolved in 200.mL of water to make a stock solution. 25mL of this stock solution is added to 75mL of water to make a more dilute solution. What is the final molarity of the diluted solution?

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.