In 1961, the Reference for the Atomic Mass Unit (Amu

question 79

Multiple Choice

In 1961, the reference for the atomic mass unit (amu or u) was changed from naturally occurring oxygen with a value of 16.000 u to one based on a single isotope of carbon (carbon-12) . Why was it changed?

• A) The atomic composition of oxygen varies depending upon its source.
• B) Carbon-12 is more common than oxygen.
• C) Carbon exists as only one isotope, carbon-12.
• D) Carbon can combine with four atoms of hydrogen to form CH₄, methane, while oxygen only combines with two atoms of hydrogen to form water, H₂O.

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Definitions:

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Net Operating Income

The income generated from normal business operations, calculated by deducting operating expenses from gross profit.

Planning Budget

A budget established at the beginning of a planning period, reflecting the expected income and expenditures.

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The difference between the expected (budgeted) and actual amounts of revenue and expenses.