Which of the following chemical reactions will produce a precipitate?

A.3 KBr + AIPO4 → K3PO4 + AlBr3
B. ZnCl2 + Mg2SO4 → ZnSO4 + MgCl2
C. Na2CO3 + CaCl2 → CaCO3 + 2NaCl
D. NH4OH + KCI — KOH + NH4CI

Which statement best summarizes the importance of ernest rutherford’s gold foil experiment? it proved that all of john dalton’s postulates were true. it verified j. j. thomson’s work on the atomic structure. it showed that an electron circles a nucleus in a fixed-energy orbit. it showed that a nucleus occupies a small part of the whole atom.

Ineed in question 5and6 in science the subject is science

I'm a tad bit confused on how to name compounds with molar mass and was wondering what was the difference between the formulas dealing with covalent and iconic if someone could pls explain these directions that would be great