--What do you have to do to the coefficients of equation I below to get to equation II?
i) 2 [tex]SnO_{2}[/tex] + 4 [tex]H_{2}[/tex] --> 2 Sn + 4 [tex]H_{2} O[/tex]
ii) [tex]SnO_{2}[/tex] + 2 [tex]H_{2}[/tex] --> Sn + 2 [tex]H_{2} O[/tex]

--Can you divide equation II by another factor and still have it be correct? Why or why not?

--In a complete sentence, write down a method you could use to determine if an equation is written in the correct way.