CHEMISTRY SCAVENGER HUNT by linxiaoqin

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									Pre AP Chemistry Unit 1 HW Packet                      Name ______________________________________

                                WKS 1.1 – Experimentation (2 pages)
For each of the following questions, indicate the correct choice. You must also give a justification for the
answer that you chose, either using a definition or statement from the notes.
   _______1. The work of scientists usually begins with:
         a. Testing a hypothesis                                        c. Creating experiments
         b. Careful observations                                        d. Drawing conclusions
       Justification:

   _______2. A hypothesis is valid only if:
         a. It is proven correct                                        c. It can be tested
         b. It can be proven incorrect                                  d. The explanation is already known
       Justification:

   _______3. A well-tested explanation that unifies a broad range of observations is known as a(n):
         a. Hypothesis                                                c. Theory
         b. Law                                                       d. Controlled experiment
       Justification:

   _______4. Which of the following examples only includes qualitative observations of water?
         a. The liquid is clear and colorless                       c. There are 10.0 mL of the liquid.
         b. The liquid has a density of 1.0 g/mL.                   d. The liquid freezes at 0.0°C.
       Justification:

   _______5. Which of these statements is false about the scientific method?
         a. The scientific method is a cycle, where based on the results of an experiment, a scientist will
             either support or reject a hypothesis.
         b. Data can only be quantitative.
         c. Observations and research should always be done before any type of experimentation.
         d. A hypothesis should always be testable.
       Justification:

   _______6. As temperature drops to the dew point, clouds form in the atmosphere, and dew forms on ground
      surfaces. A scientist hypothesizes that adding more water molecules to the atmosphere will change the
      dew point. This hypothesis is –
          a. Valid.
          b. Invalid, as it is not testable.
          c. Invalid, as it is not conditional.
          d. Invalid, as it is not conditional or testable.
       Justification:

7. Answer the following: In an experiment to test how fertilizer affects plant growth, what should the independent
   and dependent variables be? What should some of the control variables be?




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Pre AP Chemistry Unit 1 HW Packet                      Name ______________________________________

                               WKS 1.1 – Experimentation (continued)
Each sentence below describes a step of the scientific method. Match each sentence with a step of the
scientific method listed below.
               A. Recognize a problem                 C. Test the hypothesis with an experiment
               B. Form a hypothesis                   D. Draw conclusions

   _______7.    Stephen predicted that seeds might start to grow faster if an electric current traveled through
                the soil in which they were planted.

   _______8.    Renee grew bacteria from the mouth on special plates in the laboratory. She placed drops of
                different mouthwashes on bacteria on each plate.

   _______9.    Kathy used a survey to determine how many of her classmates were left-handed and how many
                were right-handed.

   _______10. Justin wondered if dyes could be taken out of plant leaves, flowers, and stems.

   _______11. Alice soaked six different kinds of seeds in water for 24 hours. Then she planted the seeds in
              soil at a depth of 1 cm. She used the same amount of water, light, and heat for each kind of
              seed.

   _______12. Bob read about growing plants in water. He wanted to know how plants could grow without
              soil.

   _______13. Kevin said, “If I grow five seedlings in red light, I think the plants might grow faster than the
              five plants grown in white light.”

   _______14. Angela’s experiment proved that earthworms move away from light.

   _______15. Scott said, “If acid rain affects plants in a particular lake, it might affect small animals, such as
              crayfish, that live in the same water.”

   _______16. Michael fed different diets to three groups of guinea pigs. His experiment showed that guinea
              pigs need vitamin C and protein in their diets.

In each of the following incidents, lab results did not come out as expected. Identify if it was because of a
“source of error” (E) or “human mistake” (M).

   _______17. A student measured out too much of a chemical.
   _______18. The instructions of a lab said to use approximate amounts of reactants, but it would have been
              better to use more precise amounts.
   _______19. The instructions of a lab said to use a graduated cylinder to measure out a liquid, but the
              student used a beaker instead.
   _______20. A student used the same scoopula to measure out two different chemicals, but did not clean the
              scoopula between measurements.
   _______21. The atmospheric pressure of a room was assumed to be constant, but in reality, there were
              some small fluctuations.

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Pre AP Chemistry Unit 1 HW Packet                      Name ______________________________________

                              WKS 1.2 – Identifying Variables (2 pages)
Spongebob Squarepants, Mr. Krabs, and some of the characters from The Simpsons have been busy
doing a little research. Read the description for each experiment and answer the questions.

Mr. Krabs created a secret ingredient for a breath mint that he thinks will “cure” the bad
breath people get from eating crabby patties at the Krusty Krab. He asked 100 customers
with a history of bad breath to try his new breath mint. He had fifty customers (Group A)
eat a breath mint after they finished eating a crabby patty. The other fifty (Group B) also
received a breath mint after they finished the sandwich, however, it was just a regular
breath mint and did not have the secret ingredient. Both groups were told that they were
getting the breath mint that would cure their bad breath. Two hours after eating the crabby
patties, thirty customers in Group A and ten customers in Group B reported having better
breath than they normally had after eating crabby patties.

                                                      1.
      Which people are in the control group?
                                                      2.
        What is the independent variable?
                                                      3.
         What is the dependent variable?
                                                      4.
         What are some control variables?
                                                      5.
     What should Mr. Krabs’ conclusion be?
 Why do you think 10 people in group B reported       6.
                fresher breath?

                        Spongebob noticed that his favorite pants were not as clean as they used to be. His
                        friend Sandy told him that he should try using Clean-O detergent, a new laundry soap
                        she found at Sail-Mart. Spongebob made sure to wash one pair of pants in plain water
                        and another pair in water with the Clean-O detergent. After washing both pairs of pants
                        a total of three times, the pants washed in the Clean-O detergent did not appear to be
                        any cleaner than the pants washed in plain water.

What was Spongebob’s beginning question for his       7.
                experiment?
                                                      8.
        What is the independent variable?
                                                      9.
         What is the dependent variable?
                                                      10.
         What are some control variables?
                                                      11.
    What should Spongebob’s conclusion be?




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Pre AP Chemistry Unit 1 HW Packet                        Name ______________________________________

                             WKS 1.2 – Identifying Variables (continued)
                    Smithers thinks that a special juice will increase the productivity of workers. He creates two
                    groups of 50 workers each and assigns each group the same task (in this case, they're supposed
                    to staple a set of papers). Group A is given the special juice to drink while they work. Group B
                    is not given the special juice. After an hour, Smithers counts how many stacks of papers each
                    group has made. Group A made 1,587 stacks, Group B made 2,113 stacks.

                                                        12.
             Identify the control group.
                                                        13.
         What is the independent variable?
                                                        14.
          What is the dependent variable?
                                                        15.
         What are some control variables?
                                                        16.
      What should Smithers’ conclusion be?

Homer notices that his shower is covered in a strange green slime. His friend Barney tells him that
coconut juice will get rid of the green slime. Homer decides to check this out by spraying half of
the shower with coconut juice. He sprays the other half of the shower with water. After 3 days of
"treatment" there is no change in the appearance of the green slime on either side of the shower.

     What would be a good hypothesis for this           17.
                 experiment?
                                                        18.
         What is the independent variable?
                                                        19.
          What is the dependent variable?
                                                        20.
       What should Homer’s conclusion be?

                Bart believes that mice exposed to microwaves will become extra strong (maybe he's been reading
                too much Radioactive Man). He decides to perform this experiment by placing 10 mice in a
                microwave for 10 seconds. He compared these 10 mice to another 10 mice that had not been
                exposed. His test consisted of a heavy block of wood that blocked the mouse food. He found that 8
                out of 10 of the microwaved mice were able to push the block away. Seven out of 10 of the non-
                microwaved mice were able to do the same.

                                                        21.
             Identify the control group.
                                                        22.
         What is the independent variable?
                                                        23.
          What is the dependent variable?
                                                        24.
        What should Bart’s conclusion be?


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Pre AP Chemistry Unit 1 HW Packet                        Name ______________________________________

                                 WKS 1.3 - Safety and First Aid (1 page)
__________________________ 1. What do you do for a thermal burn?

__________________________ 2. What do you do if somebody cuts himself very badly?

__________________________ 3. What do you do if your lab partners faints during the lab?

__________________________ 4. What do you do if you accidentally spill a small amount of acid on your hand?

__________________________ 5. What do you do if you look down and your shirt has caught on fire?

__________________________ 6. What do you do if a small amount of chemical in an evaporating dish catches fire at
                            your lab station?

__________________________ 7. What do you do if a liquid solution splatters in your eye as you are heating a test tube
                            (and you didn’t have on your goggles)? And for how long?

__________________________ 8. What do you do if you spill an entire bottle of a toxic chemical all over your clothes?

__________________________ 9. What does NFPA stand for?

__________________________ 10. In the NFPA system, which number indicates the most severe condition?

__________________________ 11. On the NFPA diamond shown, what is the code for
                            health? What does this number mean?                                          0
__________________________ 12. On the NFPA diamond shown, what is the code for
                            flammability? What does this number mean?                               2             3
__________________________ 13. What does corrosive mean?

__________________________ 14. What does toxic mean?

__________________________15. What does carcinogenic mean?

__________________________16. What do you use to neutralize an acid spill?

__________________________17. What do you use to neutralize a base spill?

__________________________18. What should be the first thing you do in any emergency situation?

__________________________19. In what order should you mix acid and water together?

__________________________20. What is the proper way to smell a chemical?

__________________________21. When should you use the fume hood?

__________________________22. How will you know how to dispose of a chemical?

__________________________23. Where is the best place to put broken glass?

__________________________24. What does the symbol shown to the right represent?
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Pre AP Chemistry Unit 1 HW Packet                      Name ______________________________________

                                    WKS 1.4 – More Safety! (1 page)
      Identify the statement as true (T) or false (F). If the statement is false, correct the statement.

_______1.    Always pour chemicals from a large container into a small container that you can easily control.

_______2.    It is not necessary to read the experiment before coming to class.

_______3.    Dilute concentrated acids by pouring the acid into the water.

_______4.    It is OK to place excess or unused chemicals back into their original containers.

_______5.    When removing a stopper from a reagent bottle, it is important to restopper the bottle when you are
             finished.

_______6.    It is OK to pour excess or unused chemicals down the drain.

_______7.    It is OK to place broken glassware in the trashcan.

_______8.    In case of a fire, accident burn, or other emergency, notify the instructor at once after appropriate
             action has been taken.

_______9.    Long hair should be confined to keep it out of flames and chemicals.

_______10. Eye protection is not needed while you are reading in the lab even if other students are still
           performing their experiments.

_______11. When taking chemicals from a stoppered bottle always lay the stopper unprotected on the bare
           counter top before pouring.

_______12. The very last thing you should do before leaving lab is to wash your hands.

_______13. Covered drinks and bottles of water are OK in lab.

_______14. If a chemical gets into your eyes, you should immediately go to the eyewash sink located in the
           laboratory room and emerge both eyes for 15 minutes.

_______15. If a chemical gets on your skin, you should immediately go to the sink or shower and rinse the
           area under constant running water for 15 minutes.

_______16. If you spill chemicals on a balance, you should just leave the chemical there.

_______17. Always close a bottle of chemicals after use.

_______18. If you spill an acid, you should put sodium hydroxide (a base) on it to neutralize it.

_______19. Open toed shoes are allowed in chemistry lab.

_______20. It is mandatory to wear safety goggles while you or others around you are performing experiments.



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Pre AP Chemistry Unit 1 HW Packet                          Name ______________________________________

                                        WKS 1.5 - Equipment (1 page)

1. What piece of glassware is used to make very accurate
   concentrations of aqueous chemical solutions?
2. What piece of glassware is used in a titration of an acid
   with a base?
3. Name four pieces of glassware which could be used to             a.
   measure a precise amount of liquid.                              b.
                                                                    c.
                                                                    d.

4. What pieces of equipment could you use to perform
   some very small-scale reactions?
5. What is commonly used as a lid for the evaporating
   dish?
6. What piece of equipment would be best to measure the
   volume of a marble?
7. What piece of equipment would be best to measure the
   mass of a marble?
8. Which piece of equipment is useful for supporting all kinds
    of equipment set-ups?
9. What is name of the curved surface of a liquid which is
    contained in a tube?
10. Do you measure volume at the top or bottom of this
    curved surface for water?
11. If you were wanting to heat up a beaker using a flame,
    what pieces of equipment would you use?


12. Which piece of glassware counts backwards, as it
    measures how much liquid has been delivered?
13. Which pieces of glassware are better to use for holding
    reactions than for measurement?

14. Of the pieces of glassware listed on #13, which has a narrow
    opening that allows it to be stoppered?
15. Which piece of equipment is used to remove chemical out of
    a bottle?
16. If you need to empty a beaker of boiling water into the sink,   a.
    name two different pieces of equipment which you might use
    to do this.                                                     b.

17. What type of clamp is used to hold the buret on the ring
    stand?
18. Which piece of equipment is used to hold solid substances
    that are being heated?
19. Name two pieces of equipment that can be used to hold a test
    tube.
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Pre AP Chemistry Unit 1 HW Packet                   Name ______________________________________

                                 WKS 1.6 - Measurement (1 page)
Measure the following glassware to the correct number of significant figures (all certain plus one
estimated). Include appropriate metric units.
A. Graduated Cylinders (in mL):


             9                            45                         60                           50

             8                            40

             7                            35                         50                           40


             6

a. ______________           b. _____________           c. _______________          d. _____________

B. Burets (in mL):                                                     C. Beaker (in mL):

            34                       21

                                                                                            150

            35                       22                                                     100

                                                                                            50



a. ______________           b. _______________                            a. _______________

If (a) was the initial volume, and (b) was the final volume,
how much liquid was delivered from the buret?________________________

   D. Rulers (in cm):




a. _____________________               b. _____________________               c. _______________

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Pre AP Chemistry Unit 1 HW Packet                          Name ______________________________________

                    WKS 1.7 – More Measurement, Accuracy vs. Precision (1 page)
Measure the following equipment to the correct number of significant figures (all certain plus one
estimated). Include appropriate metric units.

Thermometer Measurement (in Celcius):                     Barometer Measurement (in kilopascals):


                                                     99                     100




                          1.   _________________                                               2. ____________




                                                                           Barometer
                                                                              kPa

Accuracy vs. Precision:

3.         Which is more precise, a beaker or a buret? HOW DO YOU KNOW?

4.         Which is more precise, a graduated cylinder or an Erlenmeyer flask? HOW DO YOU KNOW?


5.         Which is more precise, a volumetric flask or an Erlenmeyer flask? HOW DO YOU KNOW?


6.         In your own words, describe accuracy.


7.         In your own words, describe precision.


Four lab groups performed the same experiment three times to determine the melting point of naphthalene (moth
balls). The accepted melting point is 79.0°C. Indicate whether the following sets of data are precise, accurate, both
or neither. (Hint: Taking an average of the data will help you determine if you were accurate or not!)

       Precise, Accurate, Both or
                                          Group            Trial 1        Trial 2         Trial 3
                 Neither
     8.                                      1             76.2°C         79.5°C          81.3°C
     9.                                      2             76.2°C         76.1°C          76.3°C
     10.                                     3             86.4°C         82.8°C          81.2°C
     11.                                     4             79.1°C         78.9°C          79.2°C




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Pre AP Chemistry Unit 1 HW Packet                     Name ______________________________________

                           WKS 1.8 – Calculating Percent Error (1 page)
YES – the answers are here for you!!! This way, you can check your work to make sure you got the right
answer. YOU MUST SHOW YOUR WORK TO EARN CREDIT!
1. John uses his thermometer and finds the boiling point of ethyl alcohol to be 75.5ºC. He looks in a reference
   book and discovers that the actual boiling point of ethyl alcohol is 78.3ºC. What is the percent error?
   (3.58%)



2. Barry Um receives a laboratory report back with a “+2.77% error” written on it. He had found the mass of
   an object to be 100.30 grams. What is the actual mass of the object? (103 g)




3. The density of water at 4ºC is known to be 1.00 g/cm3. Kim experimentally found the density of water to be
   1.085 g/cm3. What is her percent error? ( - 8.5% error)




4. An object has a mass of 35.00 grams. On Huey’s balance, it weighs 34.92 grams. What is the percent error
   of his balance? (0.22 %)




5. After lab, all of Henry’s friends looked at his data and laughed and laughed! They finally told him that he
   was 31.2% too low in the boiling point he had recorded. He had recorded 50oC on his data sheet. What is
   the correct boiling point of his liquid? (72.7oC)




6. The Handbook of Chemistry and Physics lists the density of acetone to be 0.7988 g/cm3. Fred
   experimentally finds actone to have a density of 0.7914 g/ cm3. The teacher allows up to +/- 0.500% error to
   make an “A”. Did Fred make an “A”? Prove your answer. (no, 0.93 % error)




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