Question

Cellular respiration transforms glucose and oxygen into carbon dioxide, water, and energy.



C6H12O6 + 6O2 → 6CO2 + ?H2O + Energy



Based on the law of conservation of matter, what is the missing coefficient for water?


(1 point)
Responses

6
6

8
8

4
4

2
2

Answer 1

To determine the missing coefficient for water in the equation for cellular respiration, we can balance the chemical equation step-by-step.

The balanced equation for cellular respiration is:

\[
C_6H_{12}O_6 + 6O_2 \rightarrow 6CO_2 + 6H_2O + \text{Energy}
\]

Given the equation:

\[
C_6H_{12}O_6 + 6O_2 \rightarrow 6CO_2 + ?H_2O + \text{Energy}
\]

We see there are 6 molecules of carbon dioxide produced and we need to balance the number of oxygen and hydrogen atoms.

1. **Start with the glucose molecule:**
- It has 6 carbons, 12 hydrogens, and 6 oxygens.

2. **On the right side:**
- For carbon dioxide (CO2), we have \(6 \times 2 = 12\) oxygen atoms from 6CO2.
- For water (H2O), if we assume \(x\) H2O, this means we need to account for \(x \times 1 = x\) oxygen from H2O.

3. **Total oxygen on the right side:**
- Total oxygen = \(12 (from\ 6CO2) + x (from\ H2O) = 12 + x\)

4. **Now, from the reactants:**
- We started with \(6O_2\), which has \(6 \times 2 = 12\) oxygen atoms, giving us a total of 12 oxygen atoms from reactants (the glucose provides additional oxygen that contributes to the overall balance).

5. **From the equation we have:**
\[
12 + x = 12 (total\ oxygen)
\]

This implies:

\[
x = 6
\]

Thus, the balanced equation shows that the missing coefficient for water (H2O) is **6**.

So the answer is **6**.