Chemistry 152 – Homework Set 1 – Flashcards
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| True or False: Chemistry is a science that deals with the composition of matter and the changes in the composition of matter. |
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| True |
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| True or False: A theory can never be proven correct, but one experiment can prove it incorrect. |
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| True |
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| True or False: One may test a hypothesis by making measurements, noting color changes, or weighing the amount of a substance that forms in a reaction. |
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| True |
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| Which of the following is a scientific observation? 1. Water freezes at 0°C. 2. If a substance freezes at 0°C, it must be water. 3. When a substance freezes, its molecules lose potential energy. 4. Freezing and boiling are called physical changes. |
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| 1. Water freezes at 0°C. |
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| Which of the following is a definition of matter. 1 Anything that takes up space. 2 Anything with mass. 3 Stuff 4 all of the above 5 none of the above |
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| 4. all of the above |
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| True or False: A liquid has definite volume but no definite shape. |
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| True |
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| True or False: Of the three states of matter, a gas has its particles farthest apart. |
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| True |
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| Which of the following is not true of particles. 1 They are in constant motion. 2 Energy does not affect their motion. 3 They move in straight lines until they collide. 4 When they collide they bounce off. 5 They can vibrate, rotate or translate. |
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| 2. Energy does not affect their motion. |
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| Why does a solid have a definite shape while a liquid does not? 1 In a solid the particles are free to move while in a liquid they are not. 2 In a liquid, the particles are free to move while in a solid they are not. 3 In a liquid the particles do not interact with each other. 4 In a solid the particles have no space between them. |
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| 2 In a liquid, the particles are free to move while in a solid they are not. |
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| Is air a element, compound, or mixture? |
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| Mixture: Air is a mixture of nitrogen, oxygen, and other gases. |
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| Is oxygen an element, compound, or mixture? |
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| Element, Oxygen gas is a pure substance. |
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| Is sodium choride an element, compound, or mixture? |
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| Compound: Sodium chloride is a pure substance. |
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| Is wine an element, compound, or mixture? |
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| Mixture: Wine is a mixture of water, alcohol, and other substances. |
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| True or False: The two forms of pure substances are elements and compounds. |
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| True |
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| True or False: A solution is a homogeneous mixture. |
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| True |
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| True or False: Elements are the basic building blocks of all substances. |
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| True |
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| True or False: The symbols for most of the elements contain one or two letters. |
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| True |
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| True or False: The symbol for cobalt can be written as Co or CO. |
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| False |
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| Which of the following is an element? 1 blood 2 iron 3 water 4 wood |
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| 2 iron |
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| True or False: Compounds can be decomposed chemically into simpler substances. |
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| True |
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| True or False: A compound is a pure substance and cannot be separated by physical means. |
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| True |
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| True or False: A mixture is a combination of two or more substances in which the substances retain their identity. |
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| True |
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| Which of the following is not true of a gas? 1 A gas is able to be compressed into a very small volume. 2 The particles of a gas are held together by very strong attractive forces but not in a rigid form. 3 A gas presses continuously and in all directions on the vessel walls. 4 Gas particles fill the entire space in which they are contained. |
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| 2 The particles of a gas are held together by very strong attractive forces but not in a rigid form. |
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| Air is classified as a mixture because it 1 does not have a definite composition. 2 has a density of 1.29 g/mL. 3 is colorless and odorless. 4 may be liquefied. |
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| 1 does not have a definite composition. |
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| When a pure substance was analyzed, it was found to contain carbon and chlorine. This substance must be classified as 1 A compound 2 Both a mixture and a compound 3 An element 4 A mixture |
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| 1 A compound |
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| Which of the following is an example of a chemical change? 1 A heated candle turns to a liquid. 2 A sheet of copper is easy to bend and fold. 3 A mixture of baking soda and vinegar fizzes vigorously. 4 Ice changes into water. |
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| 3 A mixture of baking soda and vinegar fizzes vigorously. |
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| When a platinum wire is heated in a bunsen burner flame, the platinum gets red hot, but returns to its original appearance on cooling. Has the platinum wire undergone physical change, chemical change, or both when heated? |
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| Physical change only: The wire has undergone physical change on heating. There is no chemical change observed, as the wire appears the same after heating as before. |
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| True or False: The transformation of energy from one form to another is contrary to the law of conservation of energy. |
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| False |
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| True or False: The vaporization of liquid water is a chemical change. |
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| False |
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| True or False: In a chemical change there is a change in the composition of matter. |
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| True |
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| True or False: In a chemical change the mass of the reactants equals the mass of the products. |
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| True |
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| True or False: When copper reacts with oxygen to form copper(II) oxide, a chemical change occurs. |
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| True |
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| Color, taste, odor, density, and boiling point are all physical properties. |
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| True |
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| True or False: An unknown compound is heated; a dark purple vapor and white crystalline solid result. This is an example of a chemical change. |
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| True |
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| True or False: In a chemical change, substances are formed that are entirely different, having different properties and composition from the original material. |
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| True |
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| According to the Law of Conservation of Energy, energy 1 can be destroyed. 2 can be created and destroyed. 3 can be converted from one form to another. 4 can be created. |
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| 3 can be converted from one form to another. |
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| True or False: The Law of Conservation of Mass states that no detectable change is observed in the total mass of the substances involved in a chemical change. |
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| True |
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| True or False: Energy is the capacity of matter to do work. |
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| True |
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| When 3.06g of aluminum is burned in air, the resulting product, aluminum oxide, has a mass of 5.78g. What mass of oxygen was reacted with the aluminum? a) 8.84g b) 5.78g c) 1.89g d) 2.72g |
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| d) 2.72g |
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| Which of the following statements is true for the law of conservation of matter and energy. 1 Matter and energy can be interconverted. 2 All matter always comes from preexisting matter. 3 Energy cannot be created. 4 It only applies to nuclear reactions. |
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| 1 Matter and energy can be interconverted |
