How many atoms of cobalt are in one formula unit of cobalt (III) oxide? one two three six
2 answers:
<u>Answer:</u> The correct answer is two cobalt atoms.
<u>Explanation:</u>
Cobalt (III) oxide is a compound which is formed by the combination of cobalt and oxygen atoms.
The oxidation state of cobalt in the compound is +3 and the oxidation state of oxygen in the compound is -2.
Thus, by criss-cross method, the oxidation states of the ions becomes the subscipt of the other atom which represents the number of individual atoms in a compound. So, the chemical formula of cobalt (III) oxide becomes
In the given compound, 2 atoms of cobalt are present and 3 atoms of oxygen are there.
Thus, the correct answer is two cobalt atoms.
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Answer:
46.761g/mol
Explanation:
Given parameters:
Element = Hilarium , Hi
Isotopes: Hi- 45, Hi-46 and Hi- 48
Natural abundance of Hi-45 = 18.3%
Hi-46 = 34.5%
Hi-48 = 47.2%
Unknown:
Atomic weight of naturally occurring Hilarium = ?
Solution:
Isotopes have been studied extensively by mass spectrometry. The method is used to determine the proportion/percentage/fraction by which each of the isotopes of an element occurs in nature. The proportion is called geonormal abundance. From this we can calculate the atomic weight of an element.
We can use the expression below to find this value:
Atomic weight = m₄₅α₄₅ + m₄₆α₄₆ + m₄₈α₄₈
m is the atomic mass of each isotope and α is the abundance
Atomic weight = (45 x ) + (46 x
) + (48 x
)
Atomic weight of Hi = 8.235 + 15.870 + 22.656 = 46.761g/mol