1. Formula mass #3 71 points

2. Rb 3 PO 3 ElementNumber of atomsMass number Rb385255 P131 O31648 Total 334

3. CrC 2 O 4 ElementNumber of atomsMass number Cr152 C21224 O41664 Total 140

4. 2Rb 3 PO 3 =668 4CrC 2 O 4 =560

5. C3H7O2C3H7O2 ElementNumber of atomsMass number C31236 H717 O21632 Total 75

6. KMnO 4 ElementNumber of atomsMass number K139 Mn155 O41664 Total 158

7. Al 2 (CrO 4 ) 3 ElementNumber of atomsMass number Al22754 Cr352156 O1216192 Total 402

8. (NH 4 ) 2 C 4 H 4 O 6 ElementNumber of atomsMass number N21428 H121 C4 48 O61696 Total 184

9. 3Al 2 (CrO 4 ) 3 =1206 4(NH 4 ) 2 C 4 H 4 O 6 =736

10. SnSe ElementNumber of atomsMass number Sn1119 Se179 Total 198

11. Ge 3 As 4 ElementNumber of atomsMass number Ge373219 As475300 Total 519

12. PbI 4 ElementNumber of atomsMass number Pb1207 I4127508 Total 715

13. Cs 3 P ElementNumber of atomsMass number Cs3133399 P131 Total 430

14. Ga 2 S 3 ElementNumber of atomsMass number Ga270140 S33296 Total 236

15. BaBr 2 ElementNumber of atomsMass number Ba1137 Br280160 Total 297