Question

1. directions

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which reactant is needed to balance this equation and follow the law of conservation of mass?
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2 agno₃ 3 ag(no₃)₃ 2 ag (no₃)₄ fe₂cl₂ fe₃no₂

Explanation:

To solve this, we assume the reaction is likely a double - displacement reaction, for example, between $\ce{FeCl_{2}}$ and $\ce{AgNO_{3}}$ to form products like $\ce{AgCl}$ and $\ce{Fe(NO_{3})_{2}}$. Let's take the reaction: $\ce{FeCl_{2} +? -> Fe(NO_{3})_{2} + AgCl}$ (unbalanced).

Step 1: Analyze the atoms on each side

• For the product side, if we consider the formation of $\ce{Fe(NO_{3})_{2}}$ and $\ce{AgCl}$, let's first look at the $\ce{NO_3^-}$ and $\ce{Ag^+}$ ions.
• Let's assume the reaction is $\ce{FeCl_{2} + AgNO_{3} -> Fe(NO_{3})_{2} + AgCl}$.
• On the product side, in $\ce{Fe(NO_{3})_{2}}$, there are 2 $\ce{NO_3^-}$ ions and in $\ce{AgCl}$, let's see the number of $\ce{Ag^+}$ and $\ce{Cl^-}$ ions. From $\ce{FeCl_{2}}$, we have 2 $\ce{Cl^-}$ ions, so we need 2 $\ce{AgCl}$ to balance the $\ce{Cl^-}$ ions. And for the $\ce{NO_3^-}$ ions, since we have 2 $\ce{NO_3^-}$ in $\ce{Fe(NO_{3})_{2}}$, we need 2 $\ce{AgNO_{3}}$ (because each $\ce{AgNO_{3}}$ provides 1 $\ce{NO_3^-}$ and 1 $\ce{Ag^+}$).
• Now let's check the balanced equation: $\ce{FeCl_{2} + 2AgNO_{3} -> Fe(NO_{3})_{2} + 2AgCl}$.
• Let's verify the number of each atom:
• $\ce{Fe}$: 1 on left and 1 on right.
• $\ce{Cl}$: 2 on left (from $\ce{FeCl_{2}}$) and 2 on right (from $2\ce{AgCl}$).
• $\ce{Ag}$: 2 on left (from $2\ce{AgNO_{3}}$) and 2 on right (from $2\ce{AgCl}$).
• $\ce{NO_3^-}$: 2 on left (from $2\ce{AgNO_{3}}$) and 2 on right (from $\ce{Fe(NO_{3})_{2}}$).

The other options:

• $3\ce{Ag(NO_{3})_{3}}$ would introduce an incorrect number of $\ce{NO_3^-}$ and $\ce{Ag^+}$ ions and would not balance the equation.
• $2\ce{Ag(NO_{3})_{4}}$ has an incorrect formula (the correct formula for silver nitrate is $\ce{AgNO_{3}}$, not $\ce{Ag(NO_{3})_{4}}$) and would not balance the equation.
• $\ce{Fe_{2}Cl_{2}}$ has an incorrect formula (the correct formula for iron(II) chloride is $\ce{FeCl_{2}}$) and would not help in balancing.
• $\ce{Fe_{3}NO_{2}}$ has an incorrect formula and is not a valid reactant for this type of reaction.

Answer:

$2\ \ce{AgNO_{3}}$