Part A: Doc Inmaking is trying to identify a clear colorless solvent. The possib
ID: 888342 • Letter: P
Question
Part A: Doc Inmaking is trying to identify a clear colorless solvent. The possible identities are toluene (density=0.867 g/mL), ethanol (density=0.789 g/mL), and chloroform (density=1.483 g/mL). He obtains an experimental density of 0.81 +_ 0.03 g/mL. What is the most likely identity of his sample? Is his experimental value sufficiently accurate?Toluene Ethanol Choloform Yes, accuracy is sufficient to support the identity No, accuracy is not sufficient to support the identity.
Part B: Noke Lew is trying to identify a clear colorless solvent. The possible identities are toluene (density=0.867 g/mL), ethanol (density=0.789 g/mL), and chloroform (density=1.483 g/mL). He obtains an experimental density of 0.80+_ 0.08g/mL. What is the most likely identity of his sample? Is his experimental value sufficiently accurate?
Toluene Ethanol Choloform Yes, accuracy is sufficient to support the identity No, accuracy is not sufficient to support the identity. Part A: Doc Inmaking is trying to identify a clear colorless solvent. The possible identities are toluene (density=0.867 g/mL), ethanol (density=0.789 g/mL), and chloroform (density=1.483 g/mL). He obtains an experimental density of 0.81 +_ 0.03 g/mL. What is the most likely identity of his sample? Is his experimental value sufficiently accurate?
Toluene Ethanol Choloform Yes, accuracy is sufficient to support the identity No, accuracy is not sufficient to support the identity.
Part B: Noke Lew is trying to identify a clear colorless solvent. The possible identities are toluene (density=0.867 g/mL), ethanol (density=0.789 g/mL), and chloroform (density=1.483 g/mL). He obtains an experimental density of 0.80+_ 0.08g/mL. What is the most likely identity of his sample? Is his experimental value sufficiently accurate?
Toluene Ethanol Choloform Yes, accuracy is sufficient to support the identity No, accuracy is not sufficient to support the identity. Part A: Doc Inmaking is trying to identify a clear colorless solvent. The possible identities are toluene (density=0.867 g/mL), ethanol (density=0.789 g/mL), and chloroform (density=1.483 g/mL). He obtains an experimental density of 0.81 +_ 0.03 g/mL. What is the most likely identity of his sample? Is his experimental value sufficiently accurate?
Toluene Ethanol Choloform Yes, accuracy is sufficient to support the identity No, accuracy is not sufficient to support the identity.
Part B: Noke Lew is trying to identify a clear colorless solvent. The possible identities are toluene (density=0.867 g/mL), ethanol (density=0.789 g/mL), and chloroform (density=1.483 g/mL). He obtains an experimental density of 0.80+_ 0.08g/mL. What is the most likely identity of his sample? Is his experimental value sufficiently accurate?
Toluene Ethanol Choloform Yes, accuracy is sufficient to support the identity No, accuracy is not sufficient to support the identity. Noke Lew is trying to identify a clear colorless solvent. The possible identities are toluene (density=0.867 g/mL), ethanol (density=0.789 g/mL), and chloroform (density=1.483 g/mL). He obtains an experimental density of 0.80+_ 0.08g/mL. What is the most likely identity of his sample? Is his experimental value sufficiently accurate?
Toluene Ethanol Choloform Yes, accuracy is sufficient to support the identity No, accuracy is not sufficient to support the identity.
Explanation / Answer
The accuracy of a measurement system is the degree of closeness of measurements of a quantity to the true value of the quantity.
The accuracy of a measurement can be tested by comparing it with the true value
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PART A
TOLUENE
True Value –Experimental Value (Upper) = 0.867 –( 0.81 + 0.03 ) = 0.027
True Value –Experimental Value (lower) = 0.867 –( 0.81 - 0.03 ) = 0.087
ETHANOL
True Value –Experimental Value (Upper) = 0.789 –( 0.81 + 0.03 ) = -0.051
True Value –Experimental Value (lower) = 0.789 –( 0.81 - 0.03 ) = 0.009
CHLOROFORM
True Value –Experimental Value (Upper) = 1.483 –( 0.81 + 0.03 ) = 0.643
True Value –Experimental Value (lower) = 1.483 –( 0.81 - 0.03 ) = 0.703
From these values Chloroform is ruled out immediately
At the same time the accuracy is not sufficient to support either Toluene or Ethanol
In each, one value is closer to the true value and the other is farther
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PART B
TOLUENE
True Value –Experimental Value (Upper) = 0.867 –( 0.80 + 0.08 ) = 0.013
True Value –Experimental Value (lower) = 0.867 –( 0.80 - 0.08 ) = 0.147
ETHANOL
True Value –Experimental Value (Upper) = 0.789 –( 0.80 + 0.08 )= - 0.091
True Value –Experimental Value (lower) = 0.789 –( 0.80 - 0.08 ) = 0.069
CHLOROFORM
True Value –Experimental Value (Upper) = 1.483 –( 0.80 + 0.08 ) = 0.603
True Value –Experimental Value (lower) = 1.483 –( 0.80 - 0.08 ) = 0.763
From these values Chloroform is ruled out immediately
Calculation of % error
% error = Absolute error x100/True value
TOLUENE
% error = 0.013 X100/0.867 = 1.499% For Upper limit
% error = 0.147 X100/0.867 = 16.9% For lower limit
ETHANOL
% error = 0.091 X100/0.789 = 11.53 % For Upper limit
% error = 0.069 X100/0.789= 8.74 % For lower limit
Again the accuracy is not sufficient to support either Toluene or Ethanol
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