So i have no idea how to do this problem. Permanant hard watee contains calcium sulfate and can be softened by adding sodium carbonate. Determine the number of moles sodium carbonate needed to react 27.2 moles of calcium sulfate.
a. Write the chemical equation
b. Balance the chemical equation​

This chart represents the melting point of several substance. what besy explains the high melting point of the salt?

Which statement best describes the oxidation numbers of the atoms found in magnesium chloride? a. magnesium has a 2- oxidation number and chlorine has a 1+ oxidation number. b. magnesium has a 2- oxidation number and chlorine has a 2+ oxidation number. c. magnesium has a 2+ oxidation number and chlorine has a 1- oxidation number. d. magnesium has a 1+ oxidation number and chlorine has a 1- oxidation number.

What is the empirical formula of c6h18o3? ch3o c2h5o c2h6o c2h5o5