In this question, we need to find the number of moles of CCl4 in 71.7 grams of the compound, and in order to do this, we need to use the molar mass of CCl4, 153.8g/mol, and the given mass in the question, 71.7 grams:
In order to find the molar mass of any compound, we can do it by calculating the individual mass of each element that composes the compound:
C = 12 grams
Cl = 35.45 grams, we have 4 chlorines, 4 * 35.45 = 141.8 grams
141.8 + 12 = 153.8 grams, this is the molar mass of CCl4
153.8 grams = 1 mol of CCl4
71.7 grams = x moles of CCl4
153.8x = 71.7
x = 71.7/153.8
x = 0.47 moles of CCl4
The answer will be 0.47 moles