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1. the table shows the mass of some elements. find the mass of each compoundElement | mass of an atom (amu) | element | mass of an
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2. For each of the expressions below, can you find the total number of atoms represented?A. 2MgCl2 how many- Mg: (insert answer)
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3. Tells you the number of atoms of an element in a chemical formulaQuestion 6 options: subscript coefficient molecule chemical
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4. Tells you how many molecules are present in a chemical formulaQuestion 7 options: subscript coefficient product chemical symbol
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5. H2SO4How many sulfur atoms are present in the formula shown?
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6. Which of the following best describes what happens when a substance is in the gaseous state?Group of answer choices the
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7. Which of the following best describes what happens when a substance is in the liquid state?Group of answer choices there are
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8. What is the conversion of 140 °C to K?
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9. Which of the following best describes what happens when a substance is in the solid state?Group of answer choices there are
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10. Water boils at 100°C and turns into steam. Which similarities or differences are there between water at 100°C and steam at
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    2. asked by ...hi....
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11. Use the chemical equation to complete the activity.2Cu+S→Cu2S Copper (Cu) reacts with sulfur (S) to form copper sulfide as
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12. A student in a chemistry lab decides to stir a solution in order to make the solute dissolve faster. Why will this work?(1
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13. Which of the following could you do to increase the rate of dissolution of a solute in a solution?(1 point)Responses Increase
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14. Balance the following the chemical equation:_ Mg + _ F2 → _ MgF2 a 1:1:1 b 2:1:1 c 1:2:1 d 1:1:2
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15. Question 20What is the mass number of the atom below? graph shows 3 neutrons 3 protons and 4 yellow dots a 7 b 3 c 4 d 10
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16. Which of the following elements both have chemical symbols that are two letters, and the first letter is S?(1 point) Responses
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17. Use the periodic table to identify the elements in the chemical formula K2SO4. What is the number of atoms of each element
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18. a company makes four different types of candles. The ratio of fragrance to wax for each type of candle is shown in the tables
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19. Marie discovers boxes of elements in a storage room.The boxes do not say which elements they contain, but they do have
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20. Chlorine has 2 isotopes 35 Cl and 37 Cl with percentage abundances of 75.78% and 24.22% calculate its R.A.M
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21. The atomic mass of the element niobium (Nb) is 92.906 amu. Which measurement is correct?(1 point) 1 mole of Nb = 92.906 grams 1
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22. The atomic mass of the element platinum (Pt) is 195.08 amu. How many atoms of platinumare in 195.08 grams? (1 point) 3.087 × 10
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23. For an element, how does Avogadro’s number connect the atomic and macroscopic scales?(1 point) It describes the number of
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24. The atomic mass unit is equivalent to of the mass of a neutral atom of which element?(1 point) 1 12 gold oxygen carbon hydrogen
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25. The table below lists the properties of a metallic element.A table with 1 column titled property with entries shiny, silver
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26. Which best describes a radioactive isotope?An atom is unstable. An atom is stable. There is only one other isotope. There are
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27. What trend does the reactivity of most nonmetals show in a periodic table, excluding the noble gases?random changes without any
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28. Cecil is working with samples of chlorine (Cl), oxygen (O), bromine (Br), and silver (Ag). The samples are all at room
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29. A class of elements are malleable and good conductors of electricity. They also have special properties, like strong magnetism
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30. The element tellurium (Te) has a silver-white appearance, but it is brittle. It has a high electrical conductivity and is often
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31. 1ptThe table below shows the physical properties and important uses for three elements on the periodic table. Which option
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32. 1ptWhich physical properties belong to rare-earth elements? A. brittle, high conductivity B. malleable, low conductivity C.
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33. The element silicon (Si) is important because it is used in almost all computer chips. This is because it has semiconductor
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34. The four examples often used for categories of elements are metals, nonmetals, metalloids, and rare-earth elements.Arsenic is
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35. tThe periodic table organizes elements into columns called “groups.” For example, copper (Cu), silver (Ag), and gold (Au),
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36. 1ptPart B Which statement supports your answer to Part A? A. The substance is a gas because it is malleable. B. The excellent
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37. The following equation represents the atomic masses of the reactants and products in achemical reaction. (24 + 16) + (12 + 16 +
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38. How does the formation of water from hydrogen and oxygen demonstrate the conservation ofmass? (1 point) The atomic number of the
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39. What are the elements highlighted in green classified as?A. metals B. chemicals C. metalloids D. nonmetals
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40. The atomic mass of titanium is 48 u. Which statement about titanium and carbon is correct?(1 point) The mass of one titanium
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41. The elements in group 17 of the periodic table are all called halogens. All halogens have the sameatomic number. atomic mass.
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42. Mandy is testing an unknown solution to determine whether it is an acid or a base. She places a piece of red litmus paper into
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43. This chart show the amount of radioactivity measured from three unknown isotopes.Which statement describes each of the isotopes?
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44. Which have different numbers of electrons?different ions of an element different isotopes of an element the nucleus of an
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45. Isra is analyzing the properties of several samples of elements to find out which sample is a metalloid. Which set of properties
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46. These models show the electron structures of two different nonmetal elements.Element 1 at left has a purple circle at center
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47. What best describes the states of nonmetals when they are at room temperature?Most nonmetals are gaseous, but some are liquid or
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48. The atomic number of beryllium (Be) is 4, and the atomic number of barium (Ba) is 56. Which comparison is best supported by this
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49. Which is the property of nonmetals to evaporate easily?brittle dense liquid volatile
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50. Without high specific heat,✓ would evaporate quickly. water. salt. nutrients. minerals.
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51. write a procedure for an experiment about filtration
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52. Which description is not a property of an acidA. Increase the concentration oh H+ when added to water B. Sour taste C. pH higher
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53. Which description is not a property of an acidA. Dissolves metals B. Corrosive C. Sour taste D. Slimy feel
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54. How many atoms are represented in the formula Na2HPO4? A. 8. B. 4. C. 7. D. 6.
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55. Which of the following describes what it means for a chemical equation to be balanced? A. it has the same type of atoms on both
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56. Suppose 20 atoms of hydrogen (H) react with chlorine (Cl) to produce 20 molecules of hydrochloric acid (HCl). According to the
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57. Use the chemical reaction to answer the question.2H2O2 -- 2H2O +O2 Which statement about the reaction is correct? A. the
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58. Which description of salt is a chemical property?A. Solid does not conduct electricity B. No combustion C. Salty taste D.
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59. A scientist is using a lithium-ion battery to power her laptop. Which statement about the battery is correct? A. lithium atoms
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60. When acids is added to water, hydroxide ions...A. Disappear B. Stay the same C. Decrease D. Increase
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61. Which option is an example of a chemical change? A. boiling water. B. ripping paper. C. slicing an apple. D. baking a cake.
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62. When an acid is added to water hydroxide ions... Do what?
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63. Why do elements that are in the same group of the periodic table share similar properties? A. they all have the same atomic
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64. Potassium and nickel are in the same row of the periodic table. What do these elements have in common? A. they have similar
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65. A ball-and-stick model of a molecule of formaldehyde, CH2O, is made from the following components: one black ball, one red ball,
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66. To create a molecular model, a student will use blue spheres to represent nitrogen (N) and white spheres to represent hydrogen
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67. An atomic model shows 19 protons, 20, neutrons, and 19 electrons. What is the mass number of the atom? A. 58. B. 39. C. 20. D.
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68. Is this statement true or false?The element sodium is made of two kinds of atoms with different numbers of protons. Responses
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69. hen two hydrogen atoms and one oxygen atom join together they form a molecule of what compound?Responses sodium chloride (NaCl),
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70. Is this statement true or false?Different elements can combine to form compounds. Responses true true false
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71. s this statement true or false?The atoms that make up the element oxygen are exactly the same as the atoms that make up the
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72. ook at the atom models you made in today’s activities. What are the three parts of the atom? Responses protons, molecules, and
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73. Use this paragraph: The half-life of carbon-14 is 5,700 years. A certain sample of wood has 20 grams of carbon-14 when it is
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74. Which of the following bonds is the strongest?(1 point)Responses hydrogen bonds hydrogen bonds valence bonds valence bonds
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75. What types of bonds are shown in this diagram?A diagram shows a number of structures that consist of two white balls connected
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76. What must happen for a natural resource to become a synthetic material?(1 point)Responses It needs to be pounded very thin. It
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77. What type of bonds are shown in this diagram?A diagram shows a number of circles, each marked with a ‘+,’ surrounded by a
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78. is sand a mixture
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79. Use this paragraph: The half-life of carbon-14 is 5,700 years. A certain sample of wood has 20 grams of carbon-14 when it is
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80. Which of the following patterns describes the particles of a liquid as their temperature is cooled?A. The particles slow down,
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81. Which changes occur to a sample of liquid water when its temperature is increased? Select two.A. The water boils across a wide
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82. Which procedure can be used to determine the melting point of ice?(1 point)ResponsesMix ice with water and immediately measure
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83. A student decides to conduct an investigation to determine the boiling points of water and ethanol. The student will heat
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84. Which term describes the conversion of substances into different substances?(1 point)Responses photosynthesis photosynthesis
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85. chem tech makes paper cones used to filter liquids in lab experiments. to make paper cones, the company starts with the net of
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86. Calculate the average time for the tablet to dissolve in room temperature water. Record the average time in Table A.Trial
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87. Sam is comparing the half-life of two isotopes of uranium. The half-life of Uranium-238 is 4.5×1094.5 × 10 9 years. The
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88. Why burn in a candle is physical and chemical change
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89. In a chemical change the appearance changes but the substances does not
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90. In a physical change the appearance changes but the substances does not
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91. A chemical change and chemical reaction are the same thing
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92. Examples of physical and chemical change at the same time
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93. Salt dissolving in boiling water in water is physical and chemical change
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94. what is the number of atoms in the formula 8AlF3
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95. Salt dissolving in boiling water in water is physical or chemical change
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96. Burn in propane in water is physical or chemical change
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97. Salt dissolving in water is physical or chemical change
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98. Cut paper is physical or chemical change
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99. Boiling water is physical or chemical change
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100. Melting ice is physical or chemical change
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