# Worksheet: Units of Nuclear Physics: the Unified Atomic Mass Unit

In this worksheet, we will practice converting between kilograms and unified atomic mass units.

**Q1: **

The mass of one atom of potassium-40 is 39.9640 u. What is the molar mass of potassium-40 in grams per mole?

- A 39,964.0 g/mol
- B 39.9640 g/mol
- C 0.0399640 g/mol
- D 39,964,000 g/mol
- E 3.99640 g/mol

**Q2: **

What is kg in unified atomic mass units? Give your answer to 3 significant figures.

- A 6.47 u
- B 0.0257 u
- C 3.90 u
- D 25.7 u
- E 39.0 u

**Q3: **

What is 3 u in kilograms? Give your answer to 3 significant figures.

- A kg
- B kg
- C kg
- D kg
- E kg

**Q4: **

A platinum-194 atom has a mass of 193.963 u. What is the mass of a platinum-194 atom in kilograms? Give your answer to 6 significant figures.

- A kg
- B kg
- C kg
- D kg
- E kg

**Q5: **

Uranium-238 has a molar mass of 238.051 g/mol. What is the mass of one atom of uranium-238 in unified atomic mass units?

- A 238.000 u
- B 2.38051 u
- C 238,051 u
- D 238.051 u
- E 0.238051 u

**Q6: **

What is 12.0 µg in unified atomic mass units? Give your answer to 3 significant figures.

- A u
- B u
- C u
- D u
- E u