Use the unbalanced chemical equation to answer the question.

Question

2NaHCO3 −> Na2CO3 + CO2


Which of the following can be added to the products to balance the equation?

(1 point)
Responses

O2
cap o sub 2

CH2OH
cap c cap h sub 2 cap o cap h

H2O
cap h sub 2 cap o

H2

Answer 1

To balance the unbalanced chemical equation:

\[ 2 \text{NaHCO}_3 \rightarrow \text{Na}_2\text{CO}_3 + \text{CO}_2 \]

Let's first analyze the reactants and products:

• On the left side (reactants), there are:

  • 2 Sodium (Na)
  • 2 Carbon (C)
  • 6 Oxygen (O)
  • 2 Hydrogen (H)

• On the right side (products), there are:

  • 2 Sodium (Na) (from Na2CO3)
  • 2 Carbon (C) (1 from Na2CO3 and 1 from CO2)
  • 3 Oxygen (O) (3 from Na2CO3 and 2 from CO2; total of 5)
  • No Hydrogen (H)

To balance the equation, we can add H2O to the products, which will provide the necessary hydrogen and additional oxygen to complete the balance:

Adding one molecule of H2O on the products side:

\[ 2 \text{NaHCO}_3 \rightarrow \text{Na}_2\text{CO}_3 + \text{CO}_2 + \text{H}_2\text{O} \]

Now we can count again:

• Right side after the addition:
  • Sodium: 2
  • Carbon: 2 (1 in Na2CO3 and 1 in CO2)
  • Oxygen: 6 (3 in Na2CO3, 2 in CO2, 1 in H2O; total of 6)
  • Hydrogen: 2 (from H2O)

Now both sides are balanced:

• Sodium: 2
• Carbon: 2
• Oxygen: 6
• Hydrogen: 2

Thus, adding H2O is the appropriate choice to balance the equation. The answer is:

H2O