Balancing Chemical Equations

How many Hydrogen atoms are in 4H₂O?

How many Magnesium atoms are in 10MgCl₂?

How many Nitrogen atoms are in (NH₄)₂CrO₄?

How many Hydrogen atoms in 3(NH₄)₂CrO₄?

A subscript is the small number below the element symbol that tells the number of _______ of that element.

Balance this equation: H₂ + Cl₂ ---> HCl

Balance this equation: HgO ---> Hg + O₂

How many HCl molecules do you need to balance this equation? 
Mg +  __HCl --->  MgCl₂ + H₂

Balance this equation:
P₄+O₂  -->  P₂O₃

Which of the following is balanced?
1. Mg + HCl --> H₂ + MgCl₂
2. H₂O + CO₂ --> H₂CO₃
3. KClO₃ --> KCl + O₂
4. H₂ + O₂ --> H₂O