Complete the sentence to explain why the atomic weight of carbon is reported as 12.011 in the table of elements and the periodic
table in the front inside cover of the textbook.
2 answers:
The average mass of a carbon atom 12.011, is the average of the masses of all the isotopes ¹²C and ¹³C
<h3>Further explanation</h3>The elements in nature have several types of isotopes
Isotopes are atoms whose atomic number has the same number of protons while still having a different number of neutrons.
So Isotopes are elements that have the same Atomic Number (Proton)
Atomic mass is the average atomic mass of all its isotopes
In determining the mass of an atom, as a standard is the mass of 1 carbon-12 atom whose mass is 12 amu
So the atomic mass is obtained is the mass of the atom relative to the 12th carbon atom
An atomic mass unit = amu is a relative atomic mass of 1/12 the mass of an atom of carbon-12.
The 'amu' unit has now been replaced with a unit of 'u' only
The natural abundance of ¹⁴C, ¹⁰C and ¹¹C is so small that we use the isotopes of ¹²C and ¹³C to calculate the average mass of a carbon atom
The average atomic mass is the average of the masses of all
the isotopes
Average atomic mass X = mass isotope 1. % + isotope mass 2.%
The natural abundance of ¹³C is 1.11%, and the natural abundance of ¹²C is 98.89%
The mass of ¹²C is 12 amu.
the mass of ¹³C is 13.003355 amu
so that:
average atomic mass C = (0.9889 x 12 amu) + (0.0111 x 13.00335 amu)
= 11.8668 + 0.1443
= 12,011 amu
<h3>Learn more </h3>
element X
the chemical symbols
two stable isotopes of bromine
Keywords : the isotope, C, atomic number , mass number
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Explanation:
Given
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Required
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From standard unit of conversion;
Multiply both sides by 525.4
<em>(Approximated)</em>
<em>From the list of given options, option A is the closest answer after 525.4 torr is converted to its kpa equivalent</em>