Question

practice word equations:
name each of the compounds under the question.
then, draw the lewis diagrams and balance. dont forget the states of matter!

1. sodium chloride and fluorine gas make sodium fluoride and chlorine gas.
2. the combustion of methane: ch₄ plus oxygen releases carbon dioxide and water
3. silver oxide (ag₂o) decomposes into silver metal and oxygen gas.

Explanation:

Problem 1:

Step 1: Identify Compounds and States

• Sodium chloride: \( \text{NaCl} \) (solid, \( \text{s} \))
• Fluorine gas: \( \text{F}_2 \) (gas, \( \text{g} \))
• Sodium fluoride: \( \text{NaF} \) (solid, \( \text{s} \))
• Chlorine gas: \( \text{Cl}_2 \) (gas, \( \text{g} \))

Step 2: Write Unbalanced Equation

\( \text{NaCl}(\text{s}) + \text{F}_2(\text{g})
ightarrow \text{NaF}(\text{s}) + \text{Cl}_2(\text{g}) \)

Step 3: Balance the Equation

• Balance Cl: There are 2 Cl on the right, so put 2 in front of \( \text{NaCl} \).

\( 2\text{NaCl}(\text{s}) + \text{F}_2(\text{g})
ightarrow 2\text{NaF}(\text{s}) + \text{Cl}_2(\text{g}) \)

• Check Na and F: Na: 2 on left and right; F: 2 on left and right. Balanced.

Step 4: Lewis Diagrams (Brief)

• \( \text{NaCl} \): Ionic, \( \text{Na}^+ \) and \( \text{Cl}^- \). Lewis: \( \text{Na}^+[:\ddot{\text{Cl}}:]^- \)
• \( \text{F}_2 \): Covalent, \( \text{F}::\text{F} \) (each F has 3 lone pairs)
• \( \text{NaF} \): Ionic, \( \text{Na}^+[:\ddot{\text{F}}:]^- \)
• \( \text{Cl}_2 \): Covalent, \( \text{Cl}::\text{Cl} \) (each Cl has 3 lone pairs)

Problem 2:

Step 1: Identify Compounds and States

• Methane: \( \text{CH}_4 \) (gas, \( \text{g} \))
• Oxygen gas: \( \text{O}_2 \) (gas, \( \text{g} \))
• Carbon dioxide: \( \text{CO}_2 \) (gas, \( \text{g} \))
• Water: \( \text{H}_2\text{O} \) (liquid, \( \text{l} \)) (assuming combustion, water is liquid)

Step 2: Write Unbalanced Equation

\( \text{CH}_4(\text{g}) + \text{O}_2(\text{g})
ightarrow \text{CO}_2(\text{g}) + \text{H}_2\text{O}(\text{l}) \)

Step 3: Balance the Equation

• Balance C: 1 on left and right (already balanced).
• Balance H: 4 on left, so put 2 in front of \( \text{H}_2\text{O} \).

\( \text{CH}_4(\text{g}) + \text{O}_2(\text{g})
ightarrow \text{CO}_2(\text{g}) + 2\text{H}_2\text{O}(\text{l}) \)

• Balance O: 2 on left, 2 + 2 = 4 on right. Put 2 in front of \( \text{O}_2 \).

\( \text{CH}_4(\text{g}) + 2\text{O}_2(\text{g})
ightarrow \text{CO}_2(\text{g}) + 2\text{H}_2\text{O}(\text{l}) \)

Step 4: Lewis Diagrams (Brief)

• \( \text{CH}_4 \): Tetrahedral, \( \text{H}-\text{C}-\text{H} \) (each H single bonded to C, C has no lone pairs)
• \( \text{O}_2 \): Double bond, \( \text{O}=\text{O} \) (each O has 2 lone pairs)
• \( \text{CO}_2 \): Double bonds, \( \text{O}=\text{C}=\text{O} \) (each O has 2 lone pairs)
• \( \text{H}_2\text{O} \): Bent, \( \text{H}-\text{O}-\text{H} \) (O has 2 lone pairs)

Problem 3:

Step 1: Identify Compounds and States

• Silver oxide: \( \text{Ag}_2\text{O} \) (solid, \( \text{s} \))
• Silver metal: \( \text{Ag} \) (solid, \( \text{s} \))
• Oxygen gas: \( \text{O}_2 \) (gas, \( \text{g} \))

Step 2: Write Unbalanced Equation

\( \text{Ag}_2\text{O}(\text{s})
ightarrow \text{Ag}(\text{s}) + \text{O}_2(\text{g}) \)

Step 3: Balance the Equation

• Balance O: 1 on left, 2 on right. Put 2 in front of \( \text{Ag}_2\text{O} \).

\( 2\text{Ag}_2\text{O}(\text{s})
ightarrow \text{Ag}(\text{s}) + \text{O}_2(\text{g}) \)

• Balance Ag: 4 on left, so put 4 in front of \( \text{Ag} \).

\( 2\text{Ag}_2\text{O}(\text{s})
ightarrow 4\text{Ag}(\text{s}) + \text{O}_2(\text{g}) \)

Step 4: Lewis Diagrams (Brief)

• \( \text{Ag}_2\text{O} \): Ionic, \( \text{Ag}^+ \) and \( \text{O}^{2-} \) (two \( \text{Ag}^+ \) per \( \text{O}^{2-} \))
• \( \text{Ag} \): Metallic, no Lewis diagram in the same sense (metallic bonding)
• \( \text{O}_2 \): Covalent, \( \text{O}=\text{O} \) (each O has 2 lone pairs)

Answer:

s:

1. Balanced Equation:

\( \boldsymbol{2\text{NaCl}(\text{s}) + \text{F}_2(\text{g}) = 2\text{NaF}(\text{s}) + \text{Cl}_2(\text{g})} \)

2. Balanced Equation:

\( \boldsymbol{\text{CH}_4(\text{g}) + 2\text{O}_2(\text{g}) = \text{CO}_2(\text{g}) + 2\text{H}_2\text{O}(\text{l})} \)

3. Balanced Equation:

\( \boldsymbol{2\text{Ag}_2\text{O}(\text{s}) = 4\text{Ag}(\text{s}) + \text{O}_2(\text{g})} \)

(Note: Lewis diagrams are drawn based on bonding types: ionic compounds show ions with valence electrons, covalent compounds show shared/unshared electrons. States of matter are included as \( \text{s} \) (solid), \( \text{g} \) (gas), \( \text{l} \) (liquid).)