Answer:
B. 3+
Explanation:
When Fe²⁺ loses an electron, it becomes an Fe³⁺ ion.
The loss of an electron in an atom makes the atom becomes positively charged. Further losing electrons makes the atom more positive.
For the given ion;
Fe²⁺ if it loses an electron more, it becomes Fe³⁺.
The expression is given as:
Fe²⁺ → Fe³⁺ + e⁻
D. paper d, paper c, paper a, paper b
Answer:
The Earth formed billions of years after the Universe formed
Explanation:
The "universe" is said to have been formed <em>billions of year ago</em> through an explosion. This was called the <em>"Big Bang Theory." </em>This lead to the<u> expansion of the universe</u> owing to its high temperature and density. After which, the universe cooled down. Galaxies and stars were then formed. Some of the stars died due to explosion, which then led to the <u>creation of planets</u>. Such formation of the planets happened around <u>4.5 billion years ago.</u> This is <em>9.3 billions of years later</em> than the universe was formed<em> (13.8 billions of years ago)</em>. So, this explains the answer.
B. 3.0 mol·L⁻¹ NaCl
Explanation:
Freezing point is a colligative property: it depends only on the number of particles in solution.
The for freezing point depression ΔT_f is
ΔT_f = iK_fb
where
i = the number of moles of particles available from one mole of solute
K_f = the molal freezing point depression constant
b = the molal concentration of the solute
All your solutions are aqueous NaCl. They differ only in their concentrations.
Thus, the most concentrated solution will have the greatest freezing point depression and the lowest freezing point.
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