A student measures a sample of 0.100 mol of ammonium acetate, which has a molar mass of 77.083 g/mol. The student performs the following calculations: (0.100 mol) × (77.083 g/mol) = 7.71 g of ammonium acetate (7.71 g) × (6.022 × 10²³ molecules/mol) = 4.64 × 10²⁴ molecules of ammonium acetate. What mistake did the student make in their calculations regarding the number of molecules of ammonium acetate? (1 point) Responses The student mistakenly calculated the mass instead of the number of molecules from moles. The student mistakenly calculated the mass instead of the number of molecules from moles. The student incorrectly multiplied grams by the molar mass instead of converting moles to molecules directly. The student incorrectly multiplied grams by the molar mass instead of converting moles to molecules directly. The student used the incorrect molar mass for ammonium acetate. The student used the incorrect molar mass for ammonium acetate. The student added the number of grams and molecules instead of using them separately. The student added the number of grams and molecules instead of using them separately.

Question

GPT-4o mini · Answer

The mistake the student made in their calculations regarding the number of molecules of ammonium acetate is:

The student mistakenly calculated the mass instead of the number of molecules from moles.

While the calculation of mass (7.71 g) is correct, the misinterpretation occurs during the transition from moles to molecules. The correct method involves converting directly from moles to molecules using Avogadro's number (6.022 × 10²³ molecules/mol) on the original amount of moles (0.100 mol). The calculation should be \(0.100 , \text{mol} \times 6.022 \times 10^{23} , \text{molecules/mol} = 6.022 \times 10^{22} , \text{molecules}\), not involving the mass at all.

Therefore, the student's final answer for the number of molecules of ammonium acetate is incorrect.