Unit 1 Test--Experiments "R" Us

True/False (True statements = "T", False Statements = "F")

  1. One of the safety rules is "Always be alert, serious, and responsible."

  2. Assignments are due at the end of the period.

  3. Arrangements for assignments during pre-arranged absences should be taken care of before the absence.

  4. There will be many opportunities for extra credit in Chemistry.

  5. Tests may include information from reading material not discussed in class.

  6. The calculation below shows a correct way of changing 2 inches into miles:

    Multiple Choice (Choose the best answer.)

    1. Which of the following is an inference or interpretation that is not directly observable?

      The candle gives off light and heat as it burns.

      The candle is 3.0 cm tall before burning.

      The burning candle makes little or no sound.

      The candle burns to produce carbon dioxide and water.

      The top of the candle becomes wet with a colorless liquid.

    2. Which of the above can be quantitative observations?

      A only

      B only

      C & D

      |B & C

      A & E

    3. Which of the above can be considered qualitative descriptions?

      A only

      C only

      C & D

      B & C

      A & E

    4. Which of the following is not a rule for keeping a proper laboratory notebook?

      The pages you write on must be numbered and dated.

      A table of contents should list the lab grade, title, and page number.

      It is okay to use white-out or cross out mistakes completely.

      Pages should not be ripped out from lab notebooks.

      All writing should be in ink.

    5. The reading on the following centimeter ruler is best given by:

      23. cm

      23.4 cm

      20.35 cm

      23.50 cm

      25.15 cm

    6. Which of the following problems is answered to the correct number of significant figures? (Assume all numbers are measurements.)

      14.0 / 2 = 7.0

      14.0 / 2.0 = 7

      14.0 / 2 = 7

      14.0 /2.0 = 7.00

      None

    7. Which of the following answer is the correct answer to the problem below according to the rules of addition/subtraction with significant digits?

      230.759 + 0.09 + 9.7 = ?

      240.549

      240.55

      240.5

      240.6

      240.60

    8. How many significant digits does 0.0020400 have?

      8

      7

      5

      3

      2

    9. The density of table salt is 2.164 g/cm3. What is the volume of 20.0 grams of salt?

      43.3 cm3

      0.108 cm3

      9.24 cm3

      22.2 cm3

      none of the above

    10. A student wanted to convert 10 inches to meters using the calculation at right. What, if anything, is wrong with the calculation?

      the units don't cancel correctly

      2.54 cm doesn't equal 1 inch

      100 m doesn't equal 1 cm-- 100 cm = 1 m

      all the fractions are inverted

      the calculation is correct

    11. Which of the following could be proper sources of error(s) as discussed in the conclusion of a lab write up?

      I. "I might have rounded numbers wrong"
      II. "I might not have waited long enough for the reactions to take place."
      III. "I may have made a calculation error."
      IV. "My measurement for the mass of the object could be too great, because it was wet."

      I & III only

      I, II,& IV only

      II & IV only

      I, II, & IV only

      All are OK

    Calculations (Show all work and units. Refer to the data table in question 1 for problems 1 - 5.)

    1. The denisty of an irregularly shaped object was determined using a balance and water displacement. Using the given data table, calculate the density of the object. Show all work, show units throughout your work, and use significant digits in your answer.

    Mass Object (g) . . . . . . . . . . . . . . . . 135.00
    Initial Volume Water (mL) . . . . . . . . . . 50.0
    Final Volume Object and Water (mL) .100.0

    2. Aluminum has a density of 2.70 g/mL. Could the object be pure aluminum?
    (Explain your answer in a sentence.)

    3. If the object was cut exactly in half, what would be the density of both pieces?
    (Explain your answer in a sentence or two.)

     

    4. If the object were massed while submerged in water (Density = 1.00 g/mL) what would be the apparent mass of the object in water? (Show all work and units.)

     

    5. If the object had a mass of 100.00 g while submerged in a liquid, what would be the density of the liquid? (Show all work and units.)

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