3. Which of the following processes are physical changes? Which are chemical changes? a. combustion. i. boiling b. melting c. dissolving d.

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1 Physical/Chemical Prop s and es WORKSHEET #1 1. A physical property is observed with the senses and can be determined without destroying the object. Examples of physical properties include mass, shape, color, odor, length. In a physical change, the original substance still exists. It has only changed form. 2. A chemical property indicates how a substance reacts with something else. In a chemical change, a new substance is produced. Energy changes always accompany chemical changes. Chemical changes are always accompanied by physical changes. 3. Which of the following processes are physical changes? Which are chemical changes? a. combustion e. evaporation i. boiling b. melting c. dissolving d. metabolism f. filtration g. fermentation h. distillation Identify the following properties as physical or chemical. j. electrolysis k. decomposition Physical Chemical Blue color Odor Density Luster Flammability Neutralize an acid Solubility Boiling point Supports combustion Hardness Sour taste Reacts with acid to form H 2 Melting point Reacts with water to form a gas Physical Chemical 4. Classify the following examples as physical or chemical changes. a. Sodium chloride dissolves in water b. Hydrochloric acid reacts with sodium hydroxide to produce a salt, water, and heat. c. A pellet of sodium is sliced in two pieces. d. Water is heated and changed to steam. e. Potassium chlorate decomposes to potassium chloride and oxygen gas. f. Iron rusts. g. Ice melts. h. Acid on limestone produces carbon dioxide gas. i. Wood rots. j. cracking an egg k. bake a cake

2 WORKSHEET ON CHEMICAL VS PHYSICAL PROPERTIES AND CHANGES Keep this in your binder as a study guide! You will have a quiz on this next class! Background: Keeping the difference between physical and chemical properties as well as changes can be a challenge! This worksheet will help you do this. First, use the book to define the following terms. VOCABULARY WORD DEFINITION Physical Property Physical Change Change in which the identity of the substance does NOT change Chemical Property Chemical Change Part One: Physical or Chemical Property? Fill in the chart using the vocabulary words or phrases provided. Vocabulary words Boiling point Ability to rust Melting point Brittleness Reactivity with vinegar elasticity Flammability Density Transparency ductility Each word is used once. Define the word when done! Chemical Property Definition The ability to burn Reacts with oxygen to produce rust Physical Property Definition The property of letting light pass through something Part Two: Physical or Chemical Change? Indicate with a P or a C which type of change is taking place. 1. glass breaking 10. mixing salt and water 2. hammering wood together 11. mixing oil and water 3. a rusting bicycle 12. water evaporating 4. melting butter 13. cutting grass 5. separate sand from gravel 14. burning leaves 6. bleaching your hair 15. fireworks exploding 7. frying an egg 16. cutting your hair 8. squeeze oranges for juice 17. crushing a can 9. melting ice 18. boiling water

3 Classification of Matter WS WORKSHEET #3 Directions: On a separate sheet of paper, design a classification scheme for the following. There may be many ways to accomplish this. Find one that makes sense to you: A B C D E F G H I J K L M N O P

4 Atomic Number and Mass Number WORKSHEET #4 Directions: Complete the following chart and answer the questions below: Element Name Atomic Number Number of Protons Number of Neutrons Number of Electrons Mass Number carbon hydrogen 1 hydrogen nitrogen cesium tungsten silver Use the backside of this sheet to answer the following questions. [1] How are the atomic number and the number of protons related to each other? Support. [2] How do the number of protons, number of neutrons, and the mass number relate to each other? Explain. [3] What is the one thing that determines the identity of an atom (that is, whether it is an oxygen atom or a carbon atom, etc.)? Support.

5 Atomic Structure Practice Name: Date: Period: [1] The 3 particles of the atom are: a. b. c. Their respective charges are: a. b. c. [2] The number of protons in one atom of an element determines the atom s, and the number of electrons determines of and element. [3] The atomic number tells you the number of in one atom of an element. It also tells you the number of in a neutral atom of that element. The atomic number gives the identity of an element as well as its location on the Periodic Table. No two different elements will have the atomic number. [4] The of an element is the average mass of an element s naturally occurring atom, or isotopes, taking into account the of each isotope. [5] The of an element is the total number of protons and neutrons in the of the atom. [6] The mass number is used to calculate the number of in one atom of an element. In order to calculate the number of neutrons you must subtract the from the. [7] Give the symbol and number of protons in one atom of: Lithium Bromine Iron Oxygen Krypton Copper Mercury Helium [8] Give the symbol and number of electrons in a neutral atom of: Uranium Chlorine Boron Antimony Iodine Xenon [9] Give the symbol and number of neutrons in one atom of: (To get mass number, you must round the atomic mass to the nearest whole number) Show your calculations. Barium Bismuth Carbon Fluorine Europium Hydrogen Magnesium Mercury

6 [10] Name the element which has the following numbers of particles: a. 26 electrons, 29 neutrons, 26 protons b. 53 protons, 74 neutrons c. 2 electrons (neutral atoms) d. 20 protons e. 86 electrons, 125 neutrons, 82 protons (charged atom) f. 0 neutrons [11] If you know only the following information can you always determine what the element is? (Yes/No). a. number of protons b. number of neutrons c. number of electrons in a neutral atom d. number of electrons [12] X = element symbol A = mass number [# of protons (p) + # neutrons (n)] Z = atomic number [# of protons] N = # of neutrons A - Z = N A typical isotopic symbol takes this form: ex. The isotopic symbol for Fluorine would be Fill in the missing items in the table below. Name Symbol Z A #p #e #n Isotopic Symbol Na 17 Potassium Fill in the missing items in the table below. Name Symbol Z A #p #e #n Isotopic Symbol P Iron 53 Fill in the missing items in the table below. Name Symbol Z A #p #e #n Isotopic Symbol Silver 36 W

7 ATOMIC WEIGHTS Look at the atomic weights of a few different elements on your periodic table. Do you notice that very few of the elements have atomic weights that are close to being nice whole numbers? Do you know why this is? After all, for our purposes, the mass of both the proton and the neutron are almost exactly 1, and in chemistry we usually ignore the mass of the electron because it is so very small. STUDENT PRACTICE NOTE: The numbers in each of the following problems have been made up. If we used actual percentages and masses of isotopes then you could simply look up the atomic weight of the element on the periodic table. 1. Suppose that there were two isotopes of Sodium. 28% of the naturally occurring sodium atoms had a mass of 22, and 72% atoms had a mass of 23. What would the average atomic weight of sodium be? Why then, if the mass of the atom comes mainly from the protons and neutrons it contains, don t the atomic weights of the all come out to be nice whole numbers? The reason is this; the atomic weights given on your tables are weighted averages of the weights of the different naturally occurring isotopes of the element. Let s look at an example. Approximately 75% of the chlorine atoms found in nature have a mass of 35. The other 25% have a mass of 37. What should we report as the atomic weight for chlorine? What we do is to take the weighted average of these isotopes. We multiply 75% times 35 and then add that to 25% times Suppose that there were two natural isotopes of Copper. 80% of the atoms had a mass of 63, and 20% of the atoms had a mass of 65. What would that average atomic weight of copper be? [(.75)(35)] + [(.25)(37)] = = 35.5 amu In cases where there are three known isotopes you would simply multiply each mass number by the % (expressed as a decimal) of the atoms with that mass and then add the products together. 3. Suppose that a new element (E) were discovered that existed as three natural isotopes. 25% of the atoms had a mass of 278, 38% had a mass of 281, and the remainder had a mass of 285. What would be listed as the atomic weight of this element?