Answer:
E) Two of the above statements are true.
Explanation:
The options are:
A) Before the solution is titrated with HCl it is pink and when the color changes from pink to colorless, the moles of H*(aq) equals the moles of OH"(aq) used in the hydrolysis of the neutralized aspirin. <em>TRUE. </em>Before the solution is titrated, there is an excess of NaOH (Basic solution, phenolphtalein is pink). Then, at equivalence point, after the addition of HCl, the pH is acidic and phenolphtalein is colorless.
B) Before the solution is titrated with HCl it is colorless and when the color changes from colorless to pink, the moles of H*(aq) equals the excess moles of OH(aq) added. <em>FALSE. </em>As was explained, before the titration, the solution is pink.
C) 25.0 mL of 0.100 M NaOH was added to the sample to hydrolyze the neutralized aspirin in the solution. The titration with HCl allows us to determine the moles of excess OH(aq) added. Once we determine the moles of excess OH(aq), we can determine moles of OH"(aq) used in the hydrolysis of the neutralized aspirin, which is equal to the moles of aspirin in the recrystallized aspirin. <em>TRUE. </em>Aspirin requires an excess of base (NaOH) for a complete dissolution (Hydrolysis). Then, we add H+ as HCl to know the excess moles of OH-. As we know the added moles of OH-, we can find the moles of OH that reacted = Moles of aspirin.
D) We can determine the moles of aspirin in the recrystallized aspirin by titrating with the 0.100 M NaOH to the neutralization point. The purpose of the hydrolysis of the neutralized aspirin and the back-titration with the 0.100 M HCl is to confirm the moles of aspirin in the recrystallized aspirin. <em>FALSE. </em>NaOH can be added directly unyil neutralization point because, initially, aspirin can't be dissolved completely
E) Two of the above statements are true. <em>TRUE</em>
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Right option is:
<h3>E) Two of the above statements are true.</h3>
Answer:
Some of the properties of cobalt silicate include:
It occurs as a crystal with red- violet type colour.
The shape of the cobalt silicate crystal is orthorhombic.
The molecular weight of cobalt silicate is 209.95.
The melting temperature of Cobalt Silicate is 1618 degrees Celsius.
The density of Cobalt Silicate is 4.63 grams per centimetre cube.
Cobalt Silicate can serve as a semi-conductor.
Answer:
cornell noted
Explanation:
used in middle school and can be helpful for subjects like ela history and science
(46.972* 69.472% + 48.961*21.667% + <span>49.954*8.8610%)/100% =
</span>= 46.972* 0.69472 + 48.961*0.21667 + 49.954*0.088610 =47.667 u
