Question

1. you measured the mass of the baking soda ($nahco_3$) to be 6.53 grams. calculate the number of moles of $nahco_3$ in the baking soda sample.

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hint: the molar mass of $nahco_3$ is calculated by adding all the masses from the periodic table.

Explanation:

Step1: Calculate molar mass of $\text{NaHCO}_3$

From periodic table: $\text{Na}=22.99\ \text{g/mol}$, $\text{H}=1.008\ \text{g/mol}$, $\text{C}=12.01\ \text{g/mol}$, $\text{O}=16.00\ \text{g/mol}$
$$M = 22.99 + 1.008 + 12.01 + 3\times16.00 = 84.008\ \text{g/mol}$$

Step2: Moles from mass and molar mass

Use formula $n=\frac{m}{M}$ where $m=6.53\ \text{g}$
$$n = \frac{6.53}{84.008}$$

Answer:

$0.0777$ moles (rounded to three significant figures)