Answer:
The student failed to rinse the buret with KMnO₄ solution after rinsing it with distilled water.
Explanation:
In a titration, the equivalent moles of titrant must be the same than analyte. If the student calculates an amount of moles of H₂O₂ that is larger than the actual value:
The student failed to wear goggles <em>FALSE. </em>The use of goggles doesn't change the results in the lab but you must use it!
The student did not swirl the flask appropriately and therefore stopped short of the endpoint. <em>FALSE. </em>The stopped short of the endpoint would explain a lower concentration of the real value.
The student failed to rinse the buret with KMnO₄ solution after rinsing it with distilled water. <em>TRUE. </em>If you don't rinse the buret with KMnO₄ solution the concentration of this solution in the buret will be lower than real concentration doing you spend more titrant volume overestimating the amount of H₂O₂ moles.
The student added an extra 15 mL of distilled water to the H₂O₂ solution. <em>FALSE. </em>The addition of water doesn't change the amount of H₂O₂ moles in the solution.
I hope it helps!
What are the options? I can try to give you an answer if options are provided.
Answer:
The molecular formula of the compound is C₂H₄F₂ or CH₃CHF₂
Explanation:
From the question given above, the following data were obtained:
Empirical formula of the compound = CH₂F
Fórmula mass of compound = 66 g/mol
Molecular formula of the compound =?
The molecular formula of the compound can be obtained as follow:
Molecular formula = [Empirical formula]ₙ
Molecular formula = [CH₂F]ₙ
[CH₂F]ₙ = 66
[12 + (2×1) + 19] n = 66
[12 + 2+ 19]n = 66
33n = 66
Divide both side by 33
n = 66/33
n = 2
Molecular formula = [CH₂F]ₙ
Molecular formula = [CH₂F]₂
Molecular formula = C₂H₄F₂
Thus, the molecular formula of the compound is C₂H₄F₂ or CH₃CHF₂
There are 4 electron pairs (3 bonding and 1 lone pair) so the angle is 107 degrees. The 4 electron pairs are repelled to give a tetrahedral arrangement but the molecule has a pyrimidal shape due to the lone pair.