Which of the following is closest to the precise mass of a proton?

• A. 1.008 amu
• B. 1.675 x 10^{-24} g
• C. 1.673 x 10^{-27} kg
• D. 9.109 x 10^{-31} kg

Answer: (C)

Verified step by step guidance

1. Understand that the problem asks for the precise mass of a proton, which is a fundamental particle in chemistry and physics.
2. Recall that the mass of a proton is commonly expressed in atomic mass units (amu), grams (g), or kilograms (kg), and you need to identify which given value is closest to the accepted precise mass.
3. Know the approximate accepted mass of a proton: about 1.007276 amu, or equivalently about 1.6726 x 10^{-27} kg.
4. Compare each given option to the known precise mass of a proton, paying attention to the units and the order of magnitude.
5. Determine which value matches the known precise mass most closely, considering both numerical value and units.