Chemistry Packet #3

Properties and Changes

Chemical elements Find the symbols and memorize.

1. Aluminum2. Argon3. Beryllium4. Boron5. Bromine6. Calcium7. Carbon8. Chlorine9. Copper10. Fluorine11. Gold12. Iron13. Helium14. Hydrogen15. Mercury

16. Iodine17. Potassium18. Lead19. Lithium20. Magnesium21. Nitrogen22. Sodium23. Neon24. Nickel25. Oxygen26. Phosphorus27. Silver28. Sulfur29. Silicon30. Zinc

Notes on Matter

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Section 3.1 Properties of Matter

Use each of the terms below just once to complete the passage.

Matter is anything with ________________ and volume. A ________________ is a form of matter with a

uniform and unchanging composition. Substances have specific, unchanging _______________ that can be observed.

Substances have both physical and chemical properties. _______________ properties can be observed without

changing a substance’s chemical composition. Color, hardness, and _________________ are examples. Other

properties cannot be observed without changing the composition of a substance. These are called

_____________________ properties. An example is the tendency of iron to form rust when exposed to air.

Label each property as either physical or chemical.

________1. Flammable

________ 2. Forms green carbonate when exposed air

________3. Does not work with nitrogen

________4. Colorless

________ 5. Solid at normal temps and pressures

________ 6. Ability to combine with another substance

________ 7. Melting point

________ 8. Liquid at normal temps and pressures

________9. Boiling point is 100°C

________ 10. Conducts electricity

________ 11. Density is 1g/cm3

________ 12. Rusts

________13. Ignites at 20°C

________14. Freezes at 0°C

Label each drawing with one of these words: solid, liquid, gas

12. ________________ 13. ________________14. _________________

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Chemical Mass PhysicalDensity Properties Substance

For each statement below, write true or false.

______________ 15. All matter that we encounter in everyday life exists in one of three physical forms

______________ 16. A solid has definite shape and volume

______________ 17. A liquid has a definite shape and expands to the size of its container

______________ 18. A gas has both the shape and expands to the size of its container

______________ 19. The particles in a gas cannot be compressed into a smaller volume

______________ 20. Liquids tend to contract (i.e., get smaller) when heated

______________ 21. The particles in a solid are spaced far apart

______________ 22. The words gas and vapor can be used interchangeably

Notes: on changes:

What kinds of changes do these words indicate? Write each word under the correct heading. Use each word only once.

Physical Change1. ____________________2. ____________________3. ____________________4. ____________________5. ____________________6. ____________________7. ____________________8. ____________________

Chemical Change9. ____________________10. ____________________11. ____________________12. ____________________13. ____________________14. ____________________15. ____________________16. ____________________

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Boil crumple crush explodeBurn ferment freeze grindCondense melt oxidize rotCorrode rust tarnish vaporize

Chemistry Lab # 3-1Physical and Chemical Changes

Purpose: To perform a series of laboratory techniques to induce chemical or physical changes in matter and to identify the difference between chemical and physical changes in matter.

Procedure:DAY 1:1. Using a platinum wire test rod, observe the color and luster of the metal. Hold the wire in the flame of

your Bunsen burner for about two minutes. Observe the appearance of the wire while held in the hottest part of the flame. Record your observations on the data sheet.

2. Obtain a small piece of magnesium ribbon. Note the color, luster, and flexibility of the polished metal. Using the Bunsen burner in the fume hood and holding one end of the metal with forceps, ignite the other end in the burner. DO NOT LOOK DIRECTLY AT THE METAL WHILE IT IS BURNING. Record your observations on the data sheet.

3. Pour a finger’s width of dilute hydrochloric acid in a big test tube. Place a small piece of magnesium ribbon in the tube and observe carefully for any signs of a chemical action. Cap the mouth of the test tube with your thumb to collect any gas emitted from the reaction and note any changes in temperature. Remove your thumb from the mouth of the test tube and bring the flame of a burning wood splint to the opening. Record the observations on the data sheet.

4. Add three or four ml of silver nitrate solution to a small test tube. Add three or four ml of sodium chloride solution the test tube and mix. Filter the contents of the tube with small amounts of distilled water to remove the precipitate (white solid) from the tube. Discard the filtrate (liquid passing through the filter) in the lab sink. Unfold the filter paper and expose the precipitate to light for several minutes. Record your observations on the data sheet. Discard the filter paper in the waste basket when finished.

DATA TABLEPROCEDURE TYPE OF CHANGE

(Physical or Chemical)SUPPORTING EVIDENCE

1. Heating Platinum rod

2. Burning Magnesium (Mg) ribbon

3. Hydrochloric Acid (HCl) + Magnesium (Mg)

4. Silver Nitrate (AgNO3) + Sodium Chloride (NaCl)

Questions:1. What kind of evidence usually indicates that a chemical change is occurring?

2. What kind of evidence usually indicates that a physical change is occurring?

DAY 2:

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5. Combine pea sized samples if sodium chloride and sand on your Lab paper. Examine the mixture with a magnifying glass. Transfer the mixture to a clean beaker and add approximately 10 ml of distilled water to the beaker. Mix thoroughly with your stirring rod. Decant (pour off) the liquid from the mixture into an aluminum pan for use in step 6. Using your ring stand and wire gauze, heat and dry the contents of the beaker. After drying, once again examine the solid with the magnifying glass. Record your observations on the data sheet.

6. Using the decanted solution in the aluminum pan from step 5, place the pan on the ring stand to dry. After the solution has dried and the pan has cooled, examine the residue left on the slide. Compare the residue with a fresh sample of sodium chloride, using a magnifier, if necessary. Record your observations on the data sheet.

7. Add approximately one-half an Alka-Seltzer tablet to a beaker and add 15 mL of water to the beaker. Thrust a burning splint into the upper portion of the beaker. Record your observation on the data sheet. Discard the beaker’s contents in the lab sink when you are finished.

8. Add equal amount of sodium chloride and sugar to separate test tubes. (use pea sized samples) Using your test tube clamp, heat each sample in a hot flame. Watch for changes occurring as the heating proceeds. Check for an odor being generated by using the method described by your instructor. Let the contents cool and examine the residues. Record your observations on the data sheet.

DATA TABLEPROCEDURE TYPE OF CHANGE

(Physical or Chemical)SUPPORTING EVIDENCE

5. Sodium Chloride (NaCl) + Sand mixed

6. Salt (NaCl) Solution heated

7. Alka-Seltzer in water

8a. Sugar heated

8b. Salt heated

3. Use the data you obtained in this experiment to explain the difference between a chemical and a physical change.

4. Indicate whether these observations are most likely evidence for a physical or chemical change. Support your answer.

Steam condenses to a liquid on a cool surface

Baking soda fizzes in vinegar, generating bubbles

Mercury cooled to -40°C freezes into a solid

Lead II nitrate and hydrochloric acid solutions produce an insoluble (solid) substance when mixed

Section 3.3 Mixtures of MatterUse the words below to complete the concept map

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Section 3.4 Elements and CompoundsCircle the letter of the choice that best completes the statement or answers the question.

1. A substance that cannot be separated into simpler substances by physical or chemical means is a(n)

a. Compound b. Mixture c. Element d. Period

2. A chemical combination of two or more different elements is a(n)

a. Solution b. Compound c. Element d. Period

3. Which of the following is an example of an element?

a. Water b. Air c. Sugar d. Oxygen

4. Which of the following is an example of a compound?

a. Gold b. Silver c. Aspirin d. Copper

Label each substance as either an element or a compound5. __________ Silicon6. __________ Sodium chloride7. __________ Francium

8. __________ Nickel9. __________ Water

Write the symbol for each element10. _____ Neon11. _____ Calcium

12. _____ Iron13. _____ Titanium

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heterogeneous Iron sand-water mixture mattermixtures compounds pure substances homogeneouselements solutions water

14. _____ Fluorine 15. _____ Gold

Discovery Lab: Nuts & Bolts of Matter

Purpose: to make observations of Petri dishes containing various items and relate them to elements, compounds, and mixtures.

Pre-Laboratory Questions: Define the following terms:1. Homogeneous ______________________________________________2. Heterogeneous ______________________________________________3. Pure Substance ______________________________________________4. Atom ______________________________________________________5. Molecule ___________________________________________________6. Element ____________________________________________________7. Compound __________________________________________________8. Mixture _____________________________________________________

Procedure: 1. Observe the contents of the Petri dish. Assume each nut and each bolt represents an atom or group of atoms.2. Make a drawing of the contents. Identify the contents as: homogeneous or heterogeneous; pure substance or

not; all atoms, all molecules, or a combination of atoms and molecules; and element, compound, or mixture. Provide real-life examples.

3. Repeat observations for all containers.

Data:

Container Draw Contents

Homogeneous/

Heterogeneous

Pure Substance?

All atoms, all molecules, or atoms

and molecules

Element, compound, or

mixture

Real-life example

A

B

C

D

E

F

G

H

Questions:1. Would ice water (i.e., ice cubes in a glass of water) be considered a homogeneous or heterogeneous mixture?

2. Is salt water a mixture or pure substance? 7

3. Is salt (NaCl) an element, compound, or mixture?4.

Chemistry Lab #3-2Mixture Separation

Purpose: to design, develop, and implement a procedure for separation a mixture of sand, iron filings, salt, and plastic beads.

Procedure:

Data Table:

Properties Sand Iron Filings Salt Plastic Beads

Dissolves

Big enough to see

Magnetic

Total mass of the mixture:Mass of Mixture __________

Sand Iron Filings Salt Plastic Beads

Mass of

% of Total Mass

Conclusions:For each of the four components, describe a specific physical property that enabled you to separate the component from the rest of the mixture:

Salt:Sand:Iron Filings:Plastic Beads:

On a scale of 1-10 (1 = Best, 10 = worst), how successful were you in separating and recovering each of the four components? Justify your ratings based on your observations.

Salt:

Sand:Iron Filings:Plastic Beads:

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Section 3.4 Elements and Compounds

The law of definite proportions states that regardless of the amount, a compound is always composed of the same elements in the same proportion by mass:

Mass percentage of anelement (%)= massof elementmass of compound

×100 %

1. A 20.0 g sample of sucrose contains 8.4 g of carbon. What is the mass percentage of carbon in sucrose? Show your work.

2. Sucrose is 51.50% oxygen. How many grams of oxygen are in 20.0 g of sucrose? Show your work.

3. A 2 g sample of sucrose is 6.50% hydrogen. What is the mass percentage of hydrogen in 300 g of sucrose? Explain your reasoning.

4. Two compound samples are found to have the same mass percentages of the same elements. What can you conclude about the two samples?

5. For each compound in the table, fill in the ratio of the mass of oxygen to the mass of hydrogen.

Compound Mass of Oxygen Mass of Hydrogen Mass O/Mass H

H2O 16 g 2 g a.

H2O2 32 g 2 g b.

6. Write a brief statement comparing the two mass ratios from the table

7. Are H2O and H2O2 the same compound? Explain your answer.

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Chemistry Lab # 3-3Mass and Chemical Change

Purpose: To find the relationship between the masses of reactants and products in chemical reactions.

Procedure:1. Half fill a small test tube with Ca(NO3)2 (calcium nitrate) and another test tube with Na2CO3 (sodium

carbonate). Place the test tubes in a 50 ml beaker and mass the whole “system”.

2. Pour the contents of the two test tubes into the beaker and observe the reaction. Replace the test tubes in the beaker and, again, mass the whole “system”.

3. Repeat steps 1 & 2 above, this time using a full test tube of vinegar and a full test tube of baking soda. Wait 2 minutes for the reaction to proceed. Record your observations.

4. Place 4.0 grams of baking soda in a plastic pop bottle. Pour 10.0 ml of vinegar in a medium size test tube. CAUTION: IT IS IMPORTANT TO USE ONLY THE AMOUNTS LISTED ABOVE AS YOU MAY EXCEED THE PLASTIC BOTTLE’S CAPACITY AND CAUSE AN EXPLOSION!

5. Carefully, without mixing the baking soda and vinegar, slide the test tube into the pop bottle. Tightly, replace the cap on the bottle.

6. Mass the bottle “system.” (Record)

7. Mix the baking soda and vinegar by gently allowing the contents of the soda to spill into the vinegar. Mass the bottle “system” again.

Data:

System Mass Before Reaction (g)

Mass After Reaction (g) Change of Mass?

Sodium carbonate and calcium nitrate in beakerBaking soda and vinegar in beakerBaking soda and vinegar in plastic pop bottle

Observations:

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Questions/Conclusions:

1. What evidence is there that a chemical reaction occurred?

2. What is the difference between a closed and open system?

For each item in Column A, write the letter of the matching item in Column B

Column A

_____ 3. The new substances that are formed in a chemical reaction

_____ 4. A chemical reaction that involves one of more substances changing in a chemical reaction

_____ 5. States that mass is neither created nor destroyed in any process

_____ 6. The starting substances in a chemical reaction

Column B

a. Chemical change

b. Reactants

c. Products

d. Chemical equation

e. Law of conservation of mass7. In a laboratory, 178.8 g of water is separated into hydrogen gas and oxygen gas. The hydrogen gas has a mass of 20.0 g. What is the mass of the oxygen gas produced?

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Chemistry Lab # 3-4Percent of Water in a Hydrate

Purpose: To find determine the percent of water in a hydrate.

Procedure:1. Obtain a clean evaporating dish. Record this value to the nearest 0.01 g on the data sheet (B).

2. Add about 3 grams of CuSO4 in the dish. Weigh the dish and contents and record this value on the data sheet (A).

3. Place the dish on the hot plate and heat for about 12 minutes. Hold a beaker above the dish to observe the presence of emitted gas. Allow the contents and crucible to cool and then mass the dish and contents (D).

4. Reheat the dish and contents for another five minutes to make sure that all the water has been driven off the hydrate. Once again, allow the crucible and contents to cool and then mass. Record this value (F).

Data:

Before During After

A. Mass of evaporating dish and hydrate

D. Mass after 1st heating with evaporating dish

G. Mass of anhydrous (dried) salt after 2nd heating (F – B)

B. Mass of evaporating dish

E. Mass of anhydrous (dried) salt after 1st heating (D – B)

H. Mass of water in the hydrate(C – G)

C. Mass of the hydrate before heating (A – B)

F. Mass after 2nd heating with evaporating dish

Conclusions:

1. Calculate the percent of water in the hydrate: % of water=mass of water∈hydrate

mass of hydrate before heating×100 %

2. If the theoretical value of the hydrate (CuSO4 · 5H2O) is 36%. What is your percent error?

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Chapter 3 Test ReviewThings to know:

1. Properties of solids, liquids, gasses2. Explain the symbols for elements and compounds3. Label materials as pure substances, mixtures, heterogeneous mixture, homogeneous mixture, physical

change/property, chemical change/property, element, compound4. Calculate mass percent5. Complete a concept map of matter

Review questions:1. Create a table that describes the three common states of matter in terms of their shape, volume, and

compressibility. Draw a diagram that shows this.

2. What is the difference between Ni and NI3

3. Classify each of the following as a physical or chemical property/changea. Iron and oxygen form rust ______________b. Magnesium burns brightly when ignited ______________c. Oil and water do not mix ______________d. Mercury melts at -39C ______________e. Crushing an aluminum can ______________f. Aluminum combining with oxygen to form aluminum oxide ______________

4. Classify each of the following as either heterogeneous or a homogeneous mixturea. Mud puddle water ______________b. Air ______________c. Raisin muffin ______________d. Brass (alloy of copper and zinc) ______________e. A salad ______________f. Powdered drink mix dissolved in water ______________

5. Design a concept map that summarizes the relationships among matter, mixtures, pure substances, homogeneous mixtures, heterogeneous mixtures, element , compound. How would solutions fit in?

6. Explain the difference between an element and a compound.

7. A 100g sample of an unknown salt contains 64g of chlorine. What is the percent by mass of chorine in the compound?

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