Final answer:
To determine the number of moles of CCl4 in 28.3 grams, the molar mass of CCl4 is used as a conversion factor, resulting in approximately 0.184 moles, when expressed to three significant figures.
Step-by-step explanation:
To find out how many moles of CCl4 are present in 28.3 g of the compound, we need to use the molar mass of CCl4 as a conversion factor. The molar mass of CCl4 (= 12.01 g/mol for Carbon + (4 * 35.45 g/mol) for Chlorine) is approximately 153.81 g/mol.
Now, to convert grams to moles, we use the formula:
moles of CCl4 = mass (g) / molar mass (g/mol)
moles of CCl4 = 28.3 g / 153.81 g/mol
moles of CCl4 = 0.184 moles (to 3 significant figures)