potassium reacts the most vigorously.
Answer:
- <em>2NaCl → 2Na + Cl₂, ΔH = 822 kJ </em>
Explanation:
The chemical <em>equation</em> for the <em>formation of NaCl</em> is:
- Na + (1/2) Cl₂ → NaCl , ΔH = - 411 kJ
That equation means that 1 mole of NaCl is formed by the reaction of 1 mole of Na and 1/2 mole of Cl₂, with a release of energy of 411 kJ.
The <em>decomposition</em> of <em>NaCl</em> is the inverse of the <em>formation</em> reaction; thus, you swift products and reactants and inverse the sign of the <em>change in enthalpy:</em>
- NaCl → Na + 1/2 Cl₂, ΔH = 411 kJ
Since you want the decomposition of 2 moles you multiply the equation and the ΔH by 2:
- 2NaCl → 2Na + Cl₂, ΔH = 822 kJ ← answer
Answer: Percent yield = 88%
Explanation:
Given data:
Mass of C₇H₆O₃ = 200.0 g
Actual yield of aspirin = 231 g
Percent yield = ?
Solution:
Chemical equation:
C₇H₆O₃ + C₄H₆O₃ → C₉H₈O₄ + C₂H₄O₂
Number of moles of aspirin:
Number of moles = mass/molar mass
Number of moles = 200.0 g/ 138.12 g/mol
Number of moles = 1.45 mol
Now we will compare the moles of aspirin with C₇H₆O₃.
C₇H₆O₃ : C₉H₈O₄
1 : 1
1.45 : 1.45
Theoretical yield of aspirin:
Mass = number of moles × molar mass
Mass = 1.45 g × 180.158 g/mol
Mass = 261.23 g
Percent yield:
Percent yield =( actual yield / theoretical yield )× 100
Percent yield = (231 g/ 261.23 g)× 100
Percent yield = 0.88 × 100
Percent yield = 88%
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