The chemical symbol for oxygen is O. The formula for iron oxide, a type of rust, is. Fe2O3. ... ____ 10) Which of the following uses coefficients corr...
Chapter 9 Practice Test Multiple Choice Identify the choice that best completes the statement or answers the question. ____
1) Which of the following describes a chemical reaction? a) A gas is given off when a liquid boils. b) A solid forms when a liquid freezes. c) A new substance is formed with different properties. d) A solid dissolves in a liquid.
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2) Which of the following is NOT a sign of a chemical reaction? a) gas formation b) solid formation c) energy change d) state change
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3) Which of the following occurs when water freezes? a) a physical change b) a chemical reaction c) a chemical bond d) a diatomic bond
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4) What is the force that holds two atoms together called? a) a chemical solution b) a chemical mixture c) a chemical reaction d) a chemical bond
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5) How do substances form during a chemical reaction? a) Two or more substances are combined. b) Chemical bonds break; atoms rearrange; new chemical bonds form. c) A solid substance is formed in a solution. d) Chemical bonds in molecules add atoms to make more molecules.
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6) A calcium carbonate molecule has 1 calcium (Ca) atom, 3 oxygen (O) atoms, and 1 carbon (C) atom. Which of the following shows the chemical formula for calcium carbonate? a) 3CaCO b) Ca2CO2 c) CaCO3 d) CaC2O3
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7) The symbol for iron is Fe. The chemical symbol for oxygen is O. The formula for iron oxide, a type of rust, is Fe2O3. How many iron atoms are in one molecule of iron oxide? a) one b) two c) three d) four
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8) What is the charge of an ionic compound? a) 0 b) +1 c) -1 d) +2
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9) Which of the following is the product in the chemical equation N + O2→NO2? a) N b) O c) O2 d) NO2
____ 10) Which of the following uses coefficients correctly to balance the equation N2 + H2→NH3? a) N2 + 3H2 →2NH3 b) 2N2 + 2H2→ 4NH3 c) N2 + H2 →NH3 d) 3N2 + 4H2→6NH3 ____ 11) Which of the following states the law of conservation of mass? a) Atoms are rearranged in a reaction and join new molecules. b) Compounds form a new compound with different properties. c) Mass cannot be created or destroyed in a chemical reaction. d) Energy is neither created nor destroyed in a chemical reaction.
____ 12) Nitrogen dioxide is a covalent compound. How many oxygen atoms are in a nitrogen dioxide molecule? a) three b) two c) one d) none ____ 13) How many oxygen atoms are present on the reactant side of the chemical equation 4Fe + 3O2 → 2Fe2O3? a) two b) three c) four d) six ____ 14) What type of reaction occurs when chlorophyll breaks down into new substances? a) a physical reaction b) a chemical reaction c) a nuclear reaction d) an unbalanced reaction ____ 15) Which of the following is true of the new substances formed in a chemical reaction? a) Their chemical and physical properties differ from those of the original substances. b) Their properties are the same as those of the original substances. c) Only their physical properties differ from those of the original materials. d) Only their chemical properties differ from those of the original materials. ____ 16) Which of the following is a sign of a chemical reaction? a) steam on a skating rink b) ice melting on the ground c) a dissolving solid d) a solid precipitate ____ 17) How can you be sure a chemical reaction is happening? a) A solid dissolves. b) A new substance is formed. c) Water turns to steam. d) A mixture is made. ____ 18) When chemical bonds break, what do atoms do? a) change into other atoms b) become energy c) rearrange d) disappear ____ 19) What does a prefix in a chemical formula represent? a) the number of atoms of each element b) the number of chemicals c) the number of molecules d) the number of elements ____ 20) What happens to atoms in a chemical reaction? a) They are sometimes lost and never rearranged. b) They are sometimes lost, gained, or rearranged. c) They are never lost or gained, just rearranged. d) They are lost or gained, and never rearranged. ____ 21) What must be done for a chemical equation to be balanced? a) All molecules must be counted. b) All chemicals must be equal. c) All atoms must be counted. d) All atoms must be discounted. ____ 22) Which statement is true according to the law of conservation of energy? a) Energy can be created. b) Energy cannot be destroyed. c) Energy cannot be transferred. d) Energy cannot change forms. ____ 23) What happens in an exothermic reaction? a) Energy is destroyed. b) Energy is released. c) Energy is created. d) Energy is taken in.
____ 24) What happens in an endothermic reaction? a) Energy is destroyed. b) Energy is released. c) Energy is created. d) Energy is taken in. ____ 25) Which statement is true according to the law of conservation of mass? a) Mass is destroyed. b) Mass is not created. c) The mass of the reactants is greater than the mass of the products. d) The mass of the products is greater than the mass of the reactants. ____ 26) Which of the following is NOT an example of a chemical reaction? a) milk turning sour b) food being digested c) a match burning d) ice melting ____ 27) For a chemical bond to break, a) individual atoms must be present. b) energy is required. c) covalent compounds must be mixed. d) solids must be dissolved. ____ 28) A precipitate is usually a a) solid. b) gas. c) liquid. d) solution. ____ 29) If a chemical symbol in a chemical formula has no subscript, it means a) there are no atoms in the molecule. b) the element has no charge. c) the chemical is listed last in the formula. d) only one atom of the element is in the molecule. ____ 30) Which of the following is the chemical formula for a dinitrogen trioxide molecule? a) N2O3 b) 3N2O c) 2N3O2 d) NO3 ____ 31) Why does the law of conservation of mass dictate that chemical equations be balanced? a) because atoms are never gained or lost in a chemical reaction b) because elements are classified by weight c) because chemical formulas are written from left to right d) because using the wrong chemical symbol causes confusion ____ 32) Which of the following shows coefficients being used correctly to balance the equation? a) Na + Cl2→2NaCl b) Na + 2Cl2→2NaCl c) 2Na + Cl2→2NaCl2 d) 2Na + Cl2→2NaCl ____ 33) The law of conservation of energy states that energy cannot be created or a) changed. b) destroyed. c) transferred. d) developed. ____ 34) What is O2 an example of? a) chlorophyll b) a diatomic molecule c) a chemical bond d) an ion ____ 35) In the equation C + O2→CO2, CO2 is the a) coefficient. b) precipitate. c) reactant. d) product. ____ 36) Which of the following are used to balance an equation? a) subscripts b) coefficients c) reactants d) products
____ 37) How many atoms are represented in the formula CaCO3? a) three b) four c) five d) six ____ 38) Which of the following statements explains the law of conservation of energy? a) In a chemical reaction, energy is neither created nor destroyed, but can change in form. b) Energy is needed to break chemical bonds. c) Light energy is released by some exothermic reactions. d) An exothermic reaction releases energy. ____ 39) Which of the following chemical reactions illustrates an endothermic reaction? a) CaCO3 → CaO + CO2 b) 4H2 + 2O2 → 2H2O c) 6CO2 + 6H2O + energy → C6H12O6 + 6O2 d) 4KI + 2Cl2 → 4KCl + 2I2 ____ 40) Which of the following is proof that a chemical reaction has taken place? a) A solid forms in a liquid. b) The color of a liquid changes. c) A new substance with different properties is formed. d) A substance becomes noticeably warmer. ____ 41) Which of the following chemical equations is balanced? a) 3Ca + O2 → 3CaO2 b) 3Ca + 2O2 → 5CaO2 c) Ca + 2O2 → 2CaO2 d) Ca + O2 → CaO2 ____ 42) Which of the following is an example of a chemical reaction? a) ice melting in a glass of water b) paper turning soft when wet c) salt crystals forming as sea water evaporates d) leaves changing colors in the fall ____ 43) Which of the following names a covalent compound? a) aluminum sulfate b) dinitrogen dioxide c) iron oxide d) sodium chloride ____ 44) How many sodium atoms are represented in the formula 7Na 3PO4? a) 3 b) 7 c) 21 d) 28 ____ 45) Which of the following is an example of chemical bonds breaking? a) An explosive breaks rocks in a mine. b) A person breaks rocks with a hammer c) Boiling water gives off steam. d) Low temperatures cause icicles to form.
