The answer is: II.The endpoint is recorded when the solution is dark red in color rather than light pink.
The endpoint is the point at which the indicator changes colour in a colourimetric titration and that is point when titration must stop.
Phenolphthalein is colorless in acidic solutions and pink in basic solutions. If this indicator change color to dark red, more base is added and endpoint is not accurate.
If the the acid is spilled before titration, that does not make endpoint wrong and molar mass can be calculated.
In this example we can take acetic acid as carboxylic acid; basic salt sodium acetate CH₃COONa is formed from the reaction between weak acid (in this example acetic acid CH₃COOH) and strong base (in this example sodium acetate NaOH).
Balanced chemical reaction of acetic acid and sodium hydroxide:
CH₃COOH(aq) + NaOH(aq) → CH₃COONa(aq) + H₂O(l).
Neutralization is is reaction in which an acid (in this example vinegar or acetic acid CH₃COOH) and a base react quantitatively with each other.
For the absorbance of the solution in a 1.00 cm cell at 500 nm is mathematically given as
A’ = 0.16138
<h3>What is the absorbance of the solution in a 1.00 cm cell at 500 nm?</h3>
Absorbance (A) 2 – log (%T) = 2 – log (15.6) = 0.8069
Generally, the equation for the Beer’s law is mathematically given as
A = ε*c*l
0.8069 = ε*c*(5.00 )
ε*c = 0.16138 cm-1
then for when ε*c is constant
l’ = 1.00
A’ = (0.16138 cm-1)*(1.00 cm)
A’ = 0.16138
In conclusion, the absorbance of the solution in a 1.00 cm cell at 500 nm is
A’ = 0.16138
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Can not be D or B and A is not enough so C is right.
Since they both have the same momentum, the object with the larger mass has a small velocity. (Remember that mass and velocity are inversely proportional with
p=mv.) Therefore, the smaller object will have the larger KE. (KE = 1/2 ^2)
we have
work done (W)= force(F) × displacemen(s)
or, 80= F× 8
or, F= 10 N
therefore, 10 N force is required to lift the rock.