Question

balance the entire chemical reaction using an atom inventory. remember to balance each element in the reaction.

mg(oh)₂ + hcl → mgcl₂ + h₂o

when the reaction is balanced, what is the coefficient for water, h₂o?

Explanation:

Step1: Count atoms on both sides

• Reactants: \(Mg = 1\), \(O=2\), \(H = 1 + 2=3\), \(Cl = 1\)
• Products: \(Mg = 1\), \(O = 1\), \(H = 2\), \(Cl = 2\)

Step2: Balance Cl atoms

Put a coefficient of \(2\) in front of \(HCl\). The equation becomes \(Mg(OH)_2+2HCl
ightarrow MgCl_2 + H_2O\)

• Reactants: \(Mg = 1\), \(O = 2\), \(H=2 + 2 = 4\), \(Cl = 2\)
• Products: \(Mg = 1\), \(O = 1\), \(H = 2\), \(Cl = 2\)

Step3: Balance H and O atoms

Put a coefficient of \(2\) in front of \(H_2O\). The balanced equation is \(Mg(OH)_2+2HCl = MgCl_2+2H_2O\)

• Reactants: \(Mg = 1\), \(O = 2\), \(H = 4\), \(Cl = 2\)
• Products: \(Mg = 1\), \(O = 2\), \(H = 4\), \(Cl = 2\)

Answer:

\(2\)