Answer is: A. 1.1 3 1023 NiCl2 formula units.
m(NiCl₂) = 24.6 g; mass of nickel(II) chloride.
M(NiCl₂) = 129.6 g/mol; molar mass of nickel(II) chloride.
n(NiCl₂) = m(NiCl₂) ÷ M(NiCl₂).
n(NiCl₂) = 24.6 g ÷ 129.6 g/mol.
n(NiCl₂) = 0.19 mol; amount of nickel(II) chloride.
Na = 6.022·10²³ 1/mol; Avogadro constant.
N(NiCl₂) = n(NiCl₂) · Na.
N(NiCl₂) = 0.19 mol · 6.022·10²³ 1/mol.
N(NiCl₂) = 1.13·10²³; number of formula units.
Ok so because the half life is 25 years, the mass will "decrease" by half every 25 years.
So after 25 years it becomes 2 grams,
At 50 yrs it becomes one gram
At 75 years it will be half a gram
At 100 years it will be a quarter of a gram or 0.25 grams.
I.e. the final mass is 0.25 grams
<span>will metal do is when they ionize they have relatively high energies.These atoms have large diameters. The outer electrons are relatively far from the nucleus. Metals tend to lose electrons and form positive ions.</span>
Answer:
Oxidation: Cr → Cr⁴⁺ + 4 e⁻
Reduction: 4 e⁻ + O₂ → 2 O²⁻
Explanation:
Let's consider the following redox reaction.
Cr + O₂ → CrO₂
Cr is oxidized. Its oxidation number increases from 0 to +4. The corresponding half-reaction is:
Cr → Cr⁴⁺ + 4 e⁻
O is reduced. Its oxidation number decreases from 0 to -2. The corresponding half-reaction is:
4 e⁻ + O₂ → 2 O²⁻
Answer: The purpose of a hypothesis is to find the answer to a question.
Explanation:
A hypothesis is a statement which is written as a source of prediction which is based upon the assumption of the cause of a natural event or process. The purpose of the hypothesis is basically to find the relevant answers to the scientific question. It is based upon few evidences and the entire statement of the hypothesis is tested using experimental procedures.
