A 50.0 g sample of a compound contains 2.20 × 10²³ molecules. Which of the following could be this compound?

Question

Quizplus · Accepted Answer

We first need to determine the molar mass of the compound. To do this, we can use Avogadro's number (6.02 × 10²³ molecules per mole) and the given mass of the sample: 2.20 × 10²³ molecules / 6.02 × 10²³ molecules per mole = 0.365 moles 50.0 g sample / 0.365 moles = 137 g/mol Now we can look at the choices and compare their molar masses to the calculated value: A) PH₃ = 98 g/mol B) NH₃ = 80 g/mol C) PCl₃ = 137 g/mol (matches!) D) PCl₅ = 179 g/mol E) NF₃ = 94 g/mol Of the choices given, only C matches the calculated molar mass.

A 500 G Sample of a Compound Contains 2