Word or Formula Equation?

Decide whether each of the following are word or formula equations.
Language: English
Subject: Natural science > Chemistry
School grade: Saudi Arabia Saudi Arabia > Secondary

Word or Formula Equation?

Decide whether each of the following are word or formula equations.

CH4+ O2--> CO2 + H2O

Na2O + H2O--> NaOH

calcium + sulfur--> calcium sulfide

hydrogen + fluorine --> hydrogen fluoride

H2 + Cl2--> HCl