Question

What is the mass of 1.56 mol NaOH? Make sure to round to the correct number of sig figs and include the unit in your final answer.

Answer 1

To find the mass of 1.56 mol NaOH, calculate the molar mass of NaOH and multiply by the number of moles, yielding a mass of 62.4 grams when rounded to three significant figures.

Step-by-step explanation:

To calculate the mass of 1.56 mol NaOH, we follow these steps:

1. First, find the molar mass of NaOH, which is the sum of the atomic masses of sodium (Na), oxygen (O), and hydrogen (H). From the periodic table: Na = 22.990 g/mol, O = 15.999 g/mol, H = 1.008 g/mol.
2. Next, calculate the molar mass: NaOH = 22.990 g/mol (Na) + 15.999 g/mol (O) + 1.008 g/mol (H) = 39.997 g/mol.
3. Finally, multiply the molar mass of NaOH by the number of moles: 1.56 mol × 39.997 g/mol = 62.396 g.

Since the number of moles (1.56) has three significant figures, the mass of NaOH should be reported with three significant figures as well. Therefore, the mass of 1.56 mol NaOH is 62.4 grams.