Answer:

Explanation:
6.023 × 10²³ atoms of Ca are in 1 mol of Ca

Answer:
Half life is the time taken by a radio active isotope to reduce by half of its original amount. Radium-226 has a half life of 1602 years meaning that it would take 1602 years for a mass of radium to reduce by half.
Number of half lives in 9612 years = 9612/1602 = 6 half lives
New mass = Original mass x (1/2)n where n is the number of half lives.
Therefore, New mass= 500 x (1/2)∧6
= 500 x 0.015625
= 7.8125 g
Hence the mass of radium after 9612 years will be 7.8125 grams.
Explanation:
Answer:

Explanation:
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In this case, according to the rules for the oxidation states in chemical reactions, it is possible to realize that lone elements have 0 and since magnesium is in group 2A, it forms the cation Mg⁺² as it loses electrons and oxygen is in group 6A so it forms the anion O⁻²; therefore resulting oxidation numbers are:

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Answer:
Explanation:
C) What is the multiplicity of Proton-alpha's signal in this scenario when there are 2 identical protons "next door"?
Based on n+1 rule. Here n=2 (identical beta protons).
2+1=3
So the multiplicity of alpha proton is triplet, .
D) For molecules containing only single bonds (we'll discuss the influence of double bonds in a future lecture), what is the adjective that describes the position of protons that split a "next door neighbor's" signal?
The meaning of the adjective is this: the multiplicity of beta protons is singlet only (no spliting) in absence of alpha proton . But beta protons splits as doublet (n=1) in the presence of alpha proton,
E) How many bonds connect these "splitting next door neighbors"?
There are 3 bonds in between alpha and beta protons in a molecule.
F) What is the multiplicity of the Proton-betas' signal?
Following the n+1 rule, here n=1 (1 alpha proton) so 1+1=2. Hence it is a doublet.
A.) a rotation is the earth "rotating" on its axis while a revolution is the earth "revolving" around the sun so 1 rotation is from sun rise to sun rise while one revolution is from January 1st to the next January 1st