Answer:
"The last digit in any number is referred to as the estimated digit."
Explanation:
So it should be 2
Answer:
- <em>There are </em><u><em>4 moles</em></u><em> of chloride ions in 2 moles of calcium chloride.</em>
Explanation:
Start by writing the chemical formula of calcium chloride.
The suffix -ide in chloride means that chlorine is working as the ion Cl⁻, this is with oxidation state -1.
Calcium, being an alkaline earth metal, uses oxidation state +2, Ca²⁺
Then, two atoms of Cl are combined with one atom of calcium, because in this way each Cl atom will accept one electron from a Ca atom, which will donate its two valence electrons.
That is indicated in the chemical formula with subscripts: <u><em>CaCl₂</em></u>, meaning that each formula-unit of calcium chloride has 2 ions of chlorine and 1 ions of calcium, or twice the number of moles of chloride ion.
- 1 mol CaCl₂ : 1 mol Ca⁺ : 2 mol Cl⁻
⇒ 2 mol CaCl₂ : 2 mol Ca⁺ : 4 mol Cl⁻
Hence, there are 4 moles of chloride ions in 2 moles of calcium chloride.
Identity and chemical properties
Even though two grams seemed to disappear or vanish, the law of conversation of mass still holding true. Mercuric oxide, when heated, forms a gas of mercury and oxygen. During the investigation, some gas could have escaped or evaporated.
