Deck 4: Experimental Error

Question 1

A mass of approximately 10 grams is measured using weight by difference.If a vial containing calcium carbonate powder has an initial mass of 87.36 ± 0.03 g and a final mass of 76.99 ± 0.03 g,what mass of calcium carbonate was taken?

A)10.37 ± 0.04 g
B)10.37 ± 0.03 g
C)10.370 ± 0.042 g
D)10.370 ± 0.004 g
E)10.370 ± 0.005 g

Answer 1

10.37 ± 0.04 g

Question 2

Two students are tasked with determining the milligrams of chloride in a simulated soil sample.Both students extract chloride into aqueous solution and perform triplicate titration with silver nitrate solution and dichlorofluorescein indicator.The students report the following results to their laboratory instructor. If the accepted value is 36.90 mg chloride/g sample,the laboratory instructor infers that student #1's work exhibits____________________ student #2.

A)higher accuracy and higher precision than
B)higher accuracy and lower precision than
C)lower accuracy and lower precision than
D)lower accuracy and higher precision than
E)results impossible to differentiate from

Answer 2

lower accuracy and lower precision than

Question 3

The density of a solution is determined using a class A 25-mL volumetric flask and an analytical balance.If the mass of the empty volumetric flask is 26.9872 ± 0.0003 g,the mass of the flask filled with solution is 53.9820 ± 0.0003 g,and the tolerance for the flask is ± 0.03 mL,what is the density of the solution?

A)1)07979 ± 0.00001 g/mL
B)1)0798 ± 0.0004 g/mL
C)1)0798 ± 0.0003 g/mL
D)1)080 ± 0.001 g/mL
E)1)0798 ± 0.0005 g/mL

Answer 3

1)080 ± 0.001 g/mL

Question 4

____________________ is a consistent error that can be detected and corrected.

A)User error
B)Internal error
C)Systematic error
D)Random error
E)Indeterminate error

Question 5

For significant digits and calculations,the following statements are true,EXCEPT for which one(s)?
I Addition and subtraction―round off the answer according to the number of decimal places in the number with the most decimal places.
II Multiplication and division―the answer is limited to number of digits in the number with the fewest significant digits.
III Logarithms and antilogarithms ―the number of significant figures in the antilogarithm should equal the number of digits in the mantissa.

A)I
B)II
C)III
D)I and II
E)I and III

Question 6

For the paired statements below,which are TRUE for the detection of an analytical methods systematic error?

A)I and II
B)II and IV
C)I and IV
D)II,III,and IV
E)I,II,III,and IV

Question 7

Calculate the molar mass of diethyl ether,CH₃CH₂OCH₂CH₃.(C = 12.0106 ± 0.0010,H = 1.00798 ± 0.00014,and O = 15.9990 ± 0.0008).

Question 8

Calculate the mass of a concrete slab that is 51.0 cm long,17.34 cm deep,and 6.2 cm tall with a density of 5.3 g/cm³.

A)1.0 * 10³ g
B)2.9 * 10⁴ g
C)2.91 * 10⁴
D)1.03 * 10³ g
E)2.906 * 10⁴ g

Question 9

____________________ cannot be eliminated but it may be reduced by a better experiment.

A)User error
B)Internal error
C)Systematic error
D)Random error
E)Determinate error

Question 10

Calculate the mass of a heterogeneous mixture containing 139.32 grams sand,34.99 grams gravel,and 9.372 grams salt.

A)184 g
B)183.7 g
C)183.68 g
D)184.0 g
E)183.684 g

Question 11

The distance between two cities is measured and the reported value with ambiguous significant digits is:

A)740.km.
B)7.40 * 10² km.
C)740.0 km.
D)740 km.
E)7.4 *10² km.

Question 12

For which measurement has the number of significant digits been incorrectly determined?

A)12.9830 g six significant digits
B)1920.3 m five significant digits
C)0)0043 g four significant digits
D)1)003 L four significant digits
E)59.0 km three significant digits

Question 13

For a fixed absolute uncertainty,as the magnitude of the measurement____________________ ,the percent relative uncertainty____________________ .

A)increases;decreases
B)increases;increases
C)decreases;decreases
D)decreases;increases
E)increases;remains constant

Question 14

An irregular solid with a mass of 25.9863 ± 0.0003 g displaces 20.5 ± 0.2 mL of water.Calculate the density of the solid.

Question 15

Calculate the error for the molar mass of acetic acid,CH₃CO₂H.The atomic masses for each element are C = 12.0106 ± 0.0010,H = 1.00798 ± 0.00014,and O = 15.9990 ± 0.0008.

A)± 0.01₀ g/mol
B)± 0.002₆ g/mol
C)± 0.001₃ g/mol
D)± 0.004₂ g/mol
E)± 0.02₁ g/mol

Question 16

____________________ expresses the margin of uncertainty associated with a measurement.

A)Nominal uncertainty
B)Maximum uncertainty
C)Relative uncertainty
D)Minimum uncertainty
E)Absolute uncertainty

Question 17

Calculate the volume of an aquarium that is 73.1 cm long,30.1 cm deep,and 25.44 cm tall.

A)55975 cm³
B)55980.cm³
C)5.6*10⁴ cm³
D)5.60 * 10⁴ cm³
E)55975.9 cm³

Question 18

To the correct number of significant digits,what is the molarity of a sodium hydroxide solution when 12.9 grams of NaOH is dissolved in enough water to prepare 0.500 L of solution? (NaOH = 40.00 g/mol)

Question 19

Two students are tasked with determining the milligrams of chloride in a simulated soil sample.Both students extract chloride into aqueous solution and perform triplicate titration with silver nitrate solution and dichlorofluorescein indicator.The students report the following results to their laboratory instructor. If the accepted value is 36.90 mg chloride/g sample,the laboratory instructor infers that student #2's work exhibits____________________ student #1.

A)higher accuracy and higher precision than
B)higher accuracy and lower precision than
C)lower accuracy and lower precision than
D)lower accuracy and higher precision than
E)results impossible to differentiate from

Question 20

When calculating the uncertainty associated with molar mass,which of the following statements are TRUE? I Uncertainty in the mass of n identical atoms = n *(uncertainty in atomic mass for one atom. )
II Uncertainties for different elements are dependent.
III The uncertainty for the sum of the masses of different elements is calculated using the equation .
IV When summing the masses of different elements,the uncertainties for the mass of different elements are propagated as random errors.

A)I,II,and III
B)I and III
C)II,III,and IV
D)I and IV
E)II and III