Question

a teacher has given a lab student a white chemical sample and asks her to confirm that it contains 1.167 moles of sodium hydroxide (naoh). using the balance in the laboratory, what mass of naoh would the student have to find to verify that her teacher was correct? round your answer to 3 significant figures. enter the correct number in the empty box. grams

Explanation:

Step1: Calculate molar mass of NaOH

Molar mass of Na = 22.99 g/mol, O = 16.00 g/mol, H = 1.008 g/mol.
$$M_{\text{NaOH}} = 22.99 + 16.00 + 1.008 = 39.998\ \text{g/mol}$$

Step2: Relate moles to mass

Use formula $m = n \times M$, where $n=1.167\ \text{mol}$.
$$m = 1.167\ \text{mol} \times 39.998\ \text{g/mol}$$

Step3: Compute and round to 3 sig figs

Calculate the product and round.
$$m = 46.677666\ \text{g} \approx 46.7\ \text{g}$$

Answer:

46.7