EOC-Chemistry---Scientific-Investigation by hedongchenchen


									                    EOC CHEMISTRY RELEASED TEST ITEMS

                                                   3   To remove the sand first and then the salt
DIRECTIONS                                             from a mixture of sand and salt water,
Read each question carefully and choose the best       one combination of techniques you could
answer.                                                use would be to first —

                                                       A   evaporate and then distill
                                                       B   evaporate and then condense
                                                       C   filter and then evaporate
                                                       D   filter and then condense


1   For an experiment, 9.7 mL of HCl are               A student used the above ruler to
    needed. What is the best instrument to             measure the length of a nail. The length of
    use for measuring this volume?                     this nail, according to the precision of the
                                                       ruler, is —
    A   Beaker
    B   Erlenmeyer flask                               A   3.5 cm
    C   Graduated cylinder                             B   3.55 cm
    D   Test tube                                      C   3.7 cm
                                                       D   3.75 cm
2   Which of the following pieces of glassware
    can be used to measure the volume of a
    liquid with the greatest accuracy?

    A   Test tube
    B   Beaker
    C   Flask
    D   Graduated cylinder
Scientific Investigation                                                                Page 2

5   Most gases have the property of becoming     7   The element chlorine exists as two
    increasingly soluble in a liquid as the          naturally occurring isotopes. Cl-35 occurs
    temperature of the liquid decreases. Which       75% of the time and Cl-37 occurs 25% of
    graph shows this relationship?                   the time. Which of the following
                                                     calculations should be used to calculate
                                                     the correct average atomic mass of

                                                 8   A student measures the mass of a piece of
                                                     copper three times and records the results
                                                     in the following table:

                                                     The actual mass of the copper is 28.7
                                                     grams. Which of the following is
                                                     demonstrated in the student’s data?

                                                     A   Accuracy
6   How is 0.00124 expressed in proper               B   Continuity
    scientific notation?                             C   Precision
                                                     D   Reliability
    A   1.24 x 10-3
    B   0.124 x 10-2
    C   1.24
    D   1.24 x 103
Scientific Investigation                                                                  Page 3

9    The mass of an object was recorded as        12 A student wanted to calculate the formula
     9.93 g, 9.90 g, and 10.02 g, using an           for hydrated copper sulfate. After careful
     electronic analytical balance. What is the      massing, she heated the compound to
     average of these three masses expressed to      remove the water. She calculated the
     the correct number of significant figures?      formula to be CuSO4  4H2O. The actual
                                                     formula was CuSO4  5H2O. What is the
     A   9.9 g                                       most likely source of analytical error in
     B   9.95 g                                      the student’s experiment?
     C   10.0 g
     D   10.00 g                                     A The water was not completely
                                                       evaporated from the compound.
10                                                   B The actual mass of the anhydrous
                                                       CuSO4 was less than the measurement.
                                                     C The CuSO4 reacted with elemental
                                                     D The atmospheric pressure prevented
                                                       complete reaction.

                                                  13 If a student’s hand is accidentally exposed
                                                     to an acidic solution, what should be

                                                     A   Rinse the hand in a concentrated base.
                                                     B   Rinse the hand in running water.
A student conducted an experiment and was            C   Wrap the hand in paper towels.
interested in the mass of the product of the         D   Cover the hand with oil.
chemical reaction. Some results of the
experiment are shown above. What is the           14 What is the percentage of aluminum in
mass of the NaCl?                                    aluminum oxide (Al2O3)?
     A   0.75 g                                      A   47%
     B   1.75 g                                      B   48%
     C   2.25 g                                      C   53%
     D   2.50 g                                      D   54%

11 Measurement 1: 5.2 g                           15 To determine the density of corn syrup, a
   Measurement 2: 5.4 g                              student poured 3.0 mL of the liquid into a
   Measurement 3: 3 g                                10.0 mL graduated cylinder and massed
   Measurement 4: 2.45 g                             the cylinder and contents. He determined
                                                     the density to be 10.5 g/cm3. The accepted
     These data show repeated measurements           value for the density of corn syrup is 1.38
     of the same object which has a known            g/cm3. The most probable cause of error
     mass of 5.38 grams. Which measurement           was that —
     is most accurate?
                                                     A the mass and the volume were
     A   1                                             multiplied
     B   2                                           B the mass of the cylinder was included in
     C   3                                             the density formula
     D   4                                           C the graduated cylinder accuracy is only
                                                       0.5 mL
                                                     D the mass and volume were inverted in
                                                       the density formula
Scientific Investigation                                                                   Page 4

16 A student was instructed to carry out an         18
   experiment that illustrates the law of
   conservation of mass. The teacher
   indicated that the experiment should be
   carried out three times. The student plans
   to report the average of the three results.
   What can the student do to maximize the
   reliability of the data collected?

     A Report the result that came closest to the
       class average.
     B Conduct each trial using the same                 According to the above data, which of the
       balance.                                          following represents the average density
     C Report the average of the two most                for sample X using the correct number of
       similar values only.                              significant figures?
     D Perform each of the trials on different
       days.                                             A   1 g/mL
                                                         B   0.8 g/mL
17                                                       C   0.81 g/mL
                                                         D   0.821 g/mL

A chemical engineer for a fertilizer company
is determining the most efficient way to
produce ammonia. The engineer carries out
the Haber reaction under four different
conditions. According to these data, which
procedure gave the greatest percent yield?

     A   A
     B   B
     C   C
     D   D
Scientific Investigation                                                                 Page 5

19 At a constant volume, the pressure of a     21
   gas will increase as the temperature
   increases. Which of the following graphs
   shows that relationship?

                                               Which salt is most soluble in water at 90º C?

                                                    A   NaClO3
                                                    B   KNO3
                                                    C   KBr
                                                    D   NaCl

                                               22 When examining the physical properties
                                                  of an unknown substance, which of the
                                                  following characteristics is unsafe to

                                                    A   Color
                                                    B   Weight
                                                    C   Form
                                                    D   Taste

                                               23 What is the first step that should be taken
                                                  when a caustic chemical gets into a
20 A student must make a 3 M acid solution        person’s eye?
   using a 5 M acid solution. Which of these
   is the safest way to make the solution?          A   Identify the chemical
                                                    B   Call for an ambulance
    A Slowly pour the 5 M acid into water           C   Flush the affected area with water
    B Slowly add water to the 5 M acid              D   Apply a neutralizing agent
    C Mix half the acid with water, then add   24 The density of an unknown metal was
      the remaining water                         determined to be 2.85 g/mL. The actual
    D Mix half the water with the acid, then      density was 2.70 g/mL. What is the
      add the remaining acid                      percent error in this determination?

                                                    A   0.056%
                                                    B   0.15%
                                                    C   5.6%
                                                    D   94.4%
Scientific Investigation                                                                      Page 6

25 A student uses a mortar and pestle to            28 Which of these shows a volume of 1.25
   crush 1.0 g of marble chips and places              liters expressed in milliliters?
   them into a test tube. A whole 1.0 g
   marble chip is placed into a second test            A   125 mL
   tube, and 5.0 mL of 6 M HCl is added to             B   12.5 x 101 mL
   each test tube. The bubbling speed of the           C   1.25 x 102 mL
   produced CO2 gas is noted. This                     D   1.25 x 103 mL
   experiment is designed to study the effect
   of the —                                         29 A student spills a diluted acid solution on
                                                       his hand. He should —
     A introduction of a catalyst on reaction
       rate                                            A   wipe it off with a paper towel
     B type of introduced acid on reaction rate        B   let it air dry
     C surface area of a reactant on reaction          C   apply a base solution to neutralize it
       rate                                            D   rinse it off with running water
     D temperature of a reactant on reaction rate
                                                    30 A student wanted to obtain a very
26 When CuSO4  5H2O is heated in a                    accurate value for the volume of a piece of
   crucible, there is a loss of water. How             steel. He filled a 100.0 cm3 graduated
   should a student determine the amount of            cylinder to the 50.0 cm3 mark with water.
   water lost?                                         After he carefully dropped the steel into
                                                       the cylinder, the water level rose to the
     A Subtract the mass of the CuSO4 from the         55.6 cm3 level. He reported the volume of
       mass of CuSO4  5H2O                            the steel as 5.6 cm3. How could the
     B Subtract the mass of the CuSO4                 student improve the reliability of his
         5H2O from the mass of CuSO4                   analysis?
     C Add the masses of CuSO4  5H2O and
       CuSO4                                           A Report the volume as 56 mm3
     D Multiply the masses of CuSO4  5 H2O            B Fill the graduated cylinder to the 70.0 cm3
       and CuSO4                                         mark before adding the steel
                                                       C Mass the steel and report its density in
27                                                       g/cm3
                                                       D Repeat the measurement many times
                                                         and report an average value

A student designed this experiment to study
the effects of a catalyst on a reaction. Which
trial serves as the experimental control?

     A   1
     B   2
     C   3
     D   4
Scientific Investigation                                                                  Page 7
                               Key for Strand One—Scientific Investigation


                       RELEASED TEST -– CHEMISTRY ANSWER KEY

Test Sequence       Answer      Reporting Category           Reporting Category Description

       1                   C           001           Scientific Investigation
       2                   D           001           Scientific Investigation
       3                   C           001           Scientific Investigation
       4                   D           001           Scientific Investigation
       5                   C           001           Scientific Investigation
       6                   A           001           Scientific Investigation
       7                   A           001           Scientific Investigation
       8                   C           001           Scientific Investigation
       9                   B           001           Scientific Investigation
      10                   B           001           Scientific Investigation
      11                   B           001           Scientific Investigation
      12                   A           001           Scientific Investigation
      13                   B           001           Scientific Investigation
      14                   C           001           Scientific Investigation
      15                   B           001           Scientific Investigation
      16                   B           001           Scientific Investigation
      17                   B           001           Scientific Investigation
      18                   C           001           Scientific Investigation
      19                   B           001           Scientific Investigation
      20                   A           001           Scientific Investigation
      21                   B           001           Scientific Investigation
      22                   D           001           Scientific Investigation
      23                   C           001           Scientific Investigation
      24                   C           001           Scientific Investigation
      25                   C           001           Scientific Investigation
      26                   A           001           Scientific Investigation
      27                   D           001           Scientific Investigation
      28                   D           001           Scientific Investigation
      29                   D           001           Scientific Investigation
      30                   D           001           Scientific Investigation

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