Find the Symbols and Memorize

Chemistry Packet #3
Properties and Changes

Chemical elements

Find the symbols and memorize.

1. Aluminum

2. Argon

3. Beryllium

4. Boron

5. Bromine

6. Calcium

7. Carbon

8. Chlorine

9. Copper

10. Fluorine

11. Gold

12. Iron

13. Helium

14. Hydrogen

15. Mercury

16. Iodine

17. Potassium

18. Lead

19. Lithium

20. Magnesium

21. Nitrogen

22. Sodium

23. Neon

24. Nickel

25. Oxygen

26. Phosphorus

27. Silver

28. Sulfur

29. Silicon

30. Zinc

Notes on Matter
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. ______

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 Change

1. ______

2. ______

3. ______

4. ______

5. ______

6. ______

7. ______

8. ______

Chemical Change

9. ______

10. ______

11. ______

12. ______

13. ______

14. ______

15. ______

16. ______

Chemistry Lab # 3-1

Physical 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 TABLE

PROCEDURE / 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:

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 TABLE

PROCEDURE / 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 Matter

Use the words below to complete the concept map

Section 3.4 Elements and Compounds

Circle 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 compound

5. ______Silicon

6. ______Sodium chloride

7. ______Francium

8. ______Nickel

9. ______Water

Write the symbol for each element

10. _____ Neon

11. _____ Calcium

12. _____ Iron

13. _____ Titanium

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?

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

Chemistry Lab #3-2

Mixture 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:

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 an element %= mass of 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.

Chemistry Lab # 3-3

Mass 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 beaker
Baking soda and vinegar in beaker
Baking soda and vinegar in plastic pop bottle

Observations:

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 mass

7. 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?

Chemistry Lab # 3-4

Percent of Water in a Hydrate

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