write the molecular formulae of the compound formed by the following set of elements
1. Calcium + Fluorine: Calcium fluoride
Ca + F2 ----------------> CaF2
2. Hydrogen + Sulphur: Hydrogen sulphide
2H + S -------------------> H2S
3. Nitrogen and Hydrogen : Ammonia
N2 + 3H2 ----------------> 2NH3
4. Carbon and Chlorine: Carbon tetrachloride
C + 4Cl ------------------> CCl4
5. Sodium and Oxygen: Sodium oxide
4Na + 2O2 ----------------> 2Na2O
6. Carbon and oxygen: Carbon dioxide
C + O2 ---------------------> CO2