Answer:
0.92moles
Explanation:
Given reaction:
2Fe + 3Cl₂ → 2FeCl₃
Mass of FeCl₃ = 100g
Unknown:
Number of moles of Cl₂ needed = ?
Solution:
To solve this problem, we work from the known specie to the unknown.
From the mass of the FeCl₃ given, we can solve for the number of moles of the unknown.
- Number of moles of FeCl₃;
Number of moles = 
Molar mass of FeCl₃ = 56 + 3(35.5) = 162.5g/mol
Number of moles = 
= 0.62mole
From the reaction expression;
2 mole of FeCl₃ is produced from 3 moles of Cl₂
0.62 mole of FeCl₃ will be produced from 
= 0.92mole
The number of moles of Cl₂ = 0.92moles
Answer:
Only Mn⁺² is present.
Explanation:
- When an aqueous solution of NaCl is added, the Cl⁻ species is introduced. In the presence of Cl⁻, Hg₂²⁺ would precipitate as Hg₂Cl₂.
- When an aqueous solution of Na₂SO₄ is added, the SO₄⁻² species is introduced. In the presence of SO₄⁻², Ba⁺² would precipitate as BaSO₄.
No precipitate formed when either of these solutions were added, thus <u>the sample does not contain Hg₂⁺² nor Ba⁺²</u>.
- Under basic conditions Mn⁺² would precipitate as Mn(OH)₂. A precipitate formed once the solution was made basic, so <u>the sample contains Mn⁺²</u>.
Answer:
Common combustion reactions break the bonds of hydrocarbon molecules,
Explanation:
the resulting water and carbon dioxide bonds always release more energy than was used to break the original hydrocarbon bonds. That's why burning materials mainly made up of hydrocarbons produces energy and is exothermic.
Answer:
Exothermic
q = -8.03 kJ/g
Explanation:
<em>When 2 moles of Na(s) react with H₂O(l) to form NaOH(aq) and H₂(g) according to the following equation, 369 kJ of energy are evolved.</em>
The thermochemical equation is:
2 Na(s) + 2 H₂O(l) → 2 NaOH(aq) + H₂(g) ΔH = -369 kJ
Since the energy is evolved, the reaction is exothermic, which is why the enthalpy of the reaction (ΔH) is negative.
The heat released (q) per gram of Na(s) is (molar mass 22.98 g/mol):
