
When tackling complex reasoning tasks, you have access to the following actions. Use them as needed to progress through your thought process.

[ASSESS]

[ADVANCE]

[VERIFY]

[SIMPLIFY]

[SYNTHESIZE]

[PIVOT]

[OUTPUT]

You should strictly follow the format below:

[ACTION NAME]

# Your action step 1

# Your action step 2

# Your action step 3

...

Next action: [NEXT ACTION NAME]


system
Let's calculate the mass of sodium carbonate:

$$
m\left(\mathrm{Na}_{2} \mathrm{CO}_{3}\right)=n \cdot M=0.125 \cdot 106=13.25 \text{ g}
$$

Next, let's determine the mass fraction of sodium carbonate in the initial solution:

$$
\omega\left(\mathrm{Na}_{2} \mathrm{CO}_{3}\right)=\frac{m\left(\mathrm{Na}_{2} \mathrm{CO}_{3}\right) \cdot 100\%}{m_{\mathrm{p}-\mathrm{pa}}\left(\mathrm{Na}_{2} \mathrm{CO}_{3}\right)}=\frac{13.25 \cdot 100\%}{132.5}=10\%
$$

Present the answer in LaTex format: \boxed{Your answer}
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