Chapter 2: Q127CP (page 85)

Prior to 1961, the atomic mass standard was defined as of the mass of ¹⁶O. Based on that standard: (a) What was the mass of carbon-12, given the modern atomic mass of oxygen is 15.9994 amu? (b) What was the mass of potassium-39, given its modern isotopic mass is 38.9637 amu?

Short Answer

Expert verified

The mass of carbon-12 is $12.00045 amu .$ The mass of potassium-39 is $38.9652 amu$

Step by step solution

Finding the mass of carbon-12

The carbon mass on old scale can be calculated as:

$\frac{modern mass of^{16} O}{modern mass of^{12} C} = \frac{mass of^{16} O on old scale}{mass of^{12} C on old scale} \frac{15.9994}{12} = \frac{16}{m} m = 12.00045 amu$

Finding the mass of potassium-39

The atomic ratio of modern isotopic mass of potassium-39 can be denoted as,

$\frac{modern mass of^{16} O}{modern mass of^{39} K} = \frac{mass of^{16} O on old scale}{mass of^{39} K on old scale} \frac{15.9994}{38.9637} = \frac{16}{m} m = 38.9652 amu$

On solving the isotopic mass,

$Isotopic mass of^{39} K = measured mass ratio \times mass of^{16} O = 2.435 \times 21.328 amu = 51.938 amu$

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Prior to 1961, the atomic mass standard was defined as of the mass of ¹⁶O. Based on that standard: (a) What was the mass of carbon-12, given the modern atomic mass of oxygen is 15.9994 amu? (b) What was the mass of potassium-39, given its modern isotopic mass is 38.9637 amu?

Short Answer

Step by step solution

Finding the mass of carbon-12

Finding the mass of potassium-39

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Prior to 1961, the atomic mass standard was defined as of the mass of 16O. Based on that standard: (a) What was the mass of carbon-12, given the modern atomic mass of oxygen is 15.9994 amu? (b) What was the mass of potassium-39, given its modern isotopic mass is 38.9637 amu?

Short Answer

Step by step solution

Finding the mass of carbon-12

Finding the mass of potassium-39

One App. One Place for Learning.

Most popular questions from this chapter

Recommended explanations on Chemistry Textbooks

Kinetics

Ionic and Molecular Compounds

Nuclear Chemistry

Inorganic Chemistry

Making Measurements

The Earths Atmosphere

Study anywhere. Anytime. Across all devices.

Prior to 1961, the atomic mass standard was defined as of the mass of ¹⁶O. Based on that standard: (a) What was the mass of carbon-12, given the modern atomic mass of oxygen is 15.9994 amu? (b) What was the mass of potassium-39, given its modern isotopic mass is 38.9637 amu?