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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Tab Leader

In document formatting, a visual guide that fills the space in a tabbed indent with dots, dashes, or lines to direct the reader's eye across the space.

Mirror Reflection

A reversed or flipped image of an object, mimicked in a way that it appears as if seen in a mirror.

Flip Horizontal

A digital image editing process where the image is reversed along its horizontal axis, creating a mirror image.

Rotate

Changing the orientation of an object around a pivot point without altering its location.