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Scientific Method Worksheet

Put the following steps of the scientific method in the proper order.

______________ Research the problem

______________ Observe and record

______________ Make a hypothesis

_____________ Identify the problem

_____________ Arrive at a conclusion

_____________ Test the hypothesis

Match the following terms with the correct definition.

_____________ 1. Hypothesis A. Organized process to test a hypothesis

_____________ 2. Control B. An educated guess about the solution to a problem

_____________ 3. Dependent Variable C. Observations & measurements recorded

_____________ 4. Experiment D. A judgment based on the results of an experiment

_____________ 5. Conclusion E. Used to show that the result of an experiment is

really due to the condition being tested

_____________ 6. Data F. The factor that is manipulated during an experiment

_____________ 7. Independent Variable G. The response that is measured in an experiment

CAN YOU SPOT THE SCIENTIFIC METHOD?

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

_______ 8. Stephen predicted that seeds would start to grow faster if an electric current traveled through the soil in which they were planted.

_______ 9. Susan said, “If I fertilize my geranium plants, they will blossom.”

_______ 10. Jonathan’s data showed that household cockroaches moved away from raw cucumber slices.

_______ 11. Rene grew bacteria from the mouth on special plates in the laboratory. She placed drops of different mouthwashes on bacteria on each plate.

_______ 12. Kathy used a survey to determine how many of her classmates were left-handed and how many were right-handed.

_______ 13. Dana wanted to know how synthetic fibers were different from natural fibers.

_______ 14. Jose saw bats catching insects after dark. He asked, “How do bats find the insects in the dark?”

_______ 15. Justin wondered if dyes could be taken out of plant leaves, flowers, and stems.

_______ 16. Arjulia 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.

_______ 17. Bob read about growing plants in water. He wanted to know how plants could grow without soil.

_______ 18. Kevin said, “If I grow five seedlings in red light. I think the plants will grow faster than the five plants grown in white light.”

_______ 19. Angela’s experiment proved that earthworms move away from light.

_______ 20. 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.”

_______ 21. Michael fed different diets to three groups of guinea pigs. His experiment showed that guinea pigs need vitamin C and protein in their diets.

_______ 22. Kim’s experiment showed that chicken egg shells were stronger when she gave the hen food to which extra calcium had been added.

Unit 2 Matter & Energy

Practice Problems:

1. Match the following terms with the phrases below:

a. State of matter in which atoms or molecules pack close to each other in fixed locations

b. State of matter in which atoms or molecules are packed close together but are free to move around and by each other

c. Substance composed of only one type of atom or molecule

d. Matter composed of two or more different types of atoms or molecules combined in variable proportions

e. Mixture that has two or more regions with different compositions

f. Mixture that has the same composition throughout

2. Which of the following can be classified as matter?

a. atoms

b. gas

c. wind

d. liquids

e. potential energy

f. temperature

g. carbon

h. light

3. Classify each type of matter as a pure substance or a mixture. If it is a pure substance, classify it as an element or a compound. If it is a mixture, classify it as homogeneous or heterogeneous.

a. limestone (CaCo3)

b. orange juice with pulp

c. helium

d. Pacific ocean

e. Chex mix

f. Table salt

g. Brass

h. oxygen

PHYSICAL PROPERTY CHEMICAL PROPERTY

1. OBSERVED WITH SENSES 1. INDICATES HOW A SUBSTANCE REACTS WITH SOMETHING ELSE

2. DETERMINED WITHOUT 2. MATTER WILL BE CHANGED INTO A NEW SUBSTANCE AFTER THE REACTION

DESTROYING MATTER

Identify the following as a chemical (C) or physical property (P):

______1. blue color ______8. melting point

______2. density ______9. reacts with water

______3. flammability (burns) ______10. hardness

______4. solubility (dissolves) ______11. boiling point

______5. reacts with acid ______12. luster

______6. supports combustion ______13. odor

______7. sour taste ______14. reacts with air

PHYSICAL CHANGE CHEMICAL CHANGE

1. A CHANGE IN SIZE, SHAPE, STATE 1. A CHANGE IN PHYSICAL AND CHEMICAL PROPERTIES

2. NO NEW SUBSTANCE IS FORMED 2. A NEW SUBSTANCE IS FORMED

Identify the following as physical (P) or chemical (C) changes.

_____1. NaCl (Table Salt) dissolves in water. ______9. Milk sours.

_____2. Ag (Silver) tarnishes. ______10. Sugar dissolves in water.

_____3. An apple is cut. ______11. Wood rots.

_____4. Heat changes H2O to steam. ______12. Pancakes cook.

_____5. Baking soda reacts to vinger. ______13. Grass grows.

_____6. Fe (Iron) rusts. ______14. A tire is inflated.

_____7. Alcohol evaporates . ______15. Food is digested.

_____8. Ice melts. ______16. Paper towel absorbs water.

| |Scenario |Physical or Chemical |Evidence… |

| | |Change? | |

|1. |Umm! A student removes a loaf of bread hot from the oven. The |Physical |No change in substances. |

| |student cuts a slice off the loaf and spreads butter on it. | |No unexpected color change, temperature change or gas given |

| | | |off. |

|2. |Your friend decides to toast a piece of bread, but leaves it in | | |

| |the toaster too long. The bread is black and the kitchen if full| | |

| |of smoke. | | |

|3. |You forgot to dry the bread knife when you washed it and reddish | | |

| |brown spots appeared on it. | | |

|4. |You blow dry your wet hair. | | |

|5. |In baking biscuits and other quick breads, the baking powder | | |

| |reacts to release carbon dioxide bubbles. The carbon dioxide | | |

| |bubbles cause the dough to rise. | | |

|6. |You take out your best silver spoons and notice that they are | | |

| |very dull and have some black spots. | | |

|7. |A straight piece of wire is coiled to form a spring. | | |

|8. |Food color is dropped into water to give it color. | | |

|9. |Chewing food to break it down into smaller particles represents a| | |

| |_________ change, but the changing of starch into sugars by | | |

| |enzymes in the digestive system represents a ___________change. | | |

|10. |In a fireworks show, the fireworks explode giving off heat and | | |

| |light. | | |

Unit 2 Atomic Structure

Subatomic Particles

Put the correct answer in the space provided (you will need a Periodic Table):

1. What is the atomic number of oxygen (O)? _____

2. How many protons does an aluminum (Al) atom have? _____

3. How many electrons does a calcium (Ca) atom have? _____

For #4 - #6, consider a potassium (K) atom with a mass number of 41:

4. How many protons does this atom have? _____

5. How many electrons does this atom have? _____

6. How many neutrons does this atom have? _____

For #7 - #9, consider the atom with A = 95 and Z = 42: (A is the mass and Z is the atomic number)

7. How many neutrons does this atom have? _____

8. How many protons does this atom have? _____

9. What is the atomic symbol for this element? _____

For #10 - #12, consider the atom with 35 protons, 35 electrons, and 45 neutrons:

10. What is the atomic symbol for this element? _____

11. What is the atomic number of this atom? _____

12. What is the mass number of this atom? _____

For #13 - #15, consider a copper (Cu) atom with a mass number of 64:

13. What is the Z value for this atom? _____

14. What is the A value for this atom? _____

15. How many neutrons does this atom have? _____

For #16 - #18, consider the following symbol ( 14C

16. How many protons does this atom have? _____

17. How many electrons does this atom have? _____

18. How many neutrons does this atom have? _____

For #19 - #21, consider the iron (Fe) ion with an overall +3 charge and A = 56:

19. How many protons does this ion have? _____

20. How many electrons does this ion have? _____

21. How many neutrons does this ion have? _____

For #22 - #24, consider the iodine (I) ion with an overall –1 charge and A = 126:

22. How many protons does this ion have? _____

23. How many electrons does this ion have? _____

24. How many neutrons does this ion have? _____

For #25 - #26, consider an ion with 50 protons, 46 electrons, and 70 neutrons:

25. What is the charge on this ion? _____

26. What is the mass number of this ion? _____

For #26 - #27, consider an ion with 25 protons, 20 electrons, and 30 neutrons:

27. What is the charge on this ion? _____

28. What is the atomic symbol of this ion? _____

For #28 - #30, consider the following symbol ( 238U+3

29. How many protons does this ion have? _____

30. How many electrons does this ion have? _____

31. How many neutrons does this ion have? _____

The charge on an ion will involve a number and a sign. The number will always be eaual to the

number of electrons involved. For example, loss of two electrons leaves a charge of 2+ and a gain of two electrons leaves a charge of 2-. The sign will be positive if electrons are lost and negative if electrons are gained. NOTE: A cation is a positive ion, and an anion is a negative ion.

I. Determine the charges on the following ions:

1. An atom having lost two electrons ________

2. An atom having lost four electrons ________

3. An atom having gained one electron ________

4. An atom having gained three electrons ________

5. An atom having lost three electrons ________

6. An atom having gained two electrons ________

7. An atom having lost one electron ________

8. An atom having gained four electrons ________

Considering a 26Mg atom and a 26Mg2+ ion, label the following as true or false:

____ They both have the same number of protons

____ The magnesium atom has more electrons than the ion

____ The magnesium atom has less electrons than the ion

____ The magnesium atom has 14 neutrons

____ The magnesium ion has 12 neutrons

____ The magnesium atom has more protons than the ion

____ The magnesium atom and ion both have 12 neutrons

____ The magnesium ion and atom both have 12 electrons

____ The magnesium ion and atom both have 10 electrons

____ The magnesium ion has 10 electrons while the atom has 12 electrons

____ The magnesium ion has 10 electrons while the atom has 14 electron

____ Magnesium-24 and magnesium-26 atoms are two different isotopes of magnesium

with different numbers of protons

____ Magnesium-24 and magnesium-26 atoms are two different isotopes of magnesium

with different numbers of neutrons

Complete the following table of proton, electron, and neutron characteristics.

|Particle |Symbol |Location |Relative Charge |Relative Mass |

|6. Proton | | | | |

|7. |n | | | |

|8. | | | |1/1840 |

For each statement below, write true or false.

_____________________ 1. The number of neutrons in an atom is referred to as its atomic number.

_____________________ 2. The periodic table is arranged by increasing atomic number.

_____________________ 3. Atomic number is equal to the number of electrons in an atom.

_____________________ 4. The number of protons in an atom identifies it as an atom of a particular element.

_____________________ 5. Most atoms have either a positive or a negative charge.

UNIT 4 NUCLEAR CHEMISTRY

THIS IS RECENT JUST MAKE SURE YOU KNOW THE DECAYS OF ALPHA AND BETA.

MAKE SURE YOU KNOW HOW TO DO SIMLE HALF LIFE PROBLEMS

-----------------------

1. heterogeneous mixture

2. homogeneous mixture

3. liquid

4. mixture

5. pure substance

6. solid

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