front 1 Which of the following cannot be classified as a substance? | back 1 b. air |
front 2 Examples of a physical change include | back 2 d. all of the above (freezing, melting, boiling, condensing, cutting, grinding) |
front 3 Which statement is true of any chemical reaction? | back 3 d. The mass of the reactants equals the mass of the products. |
front 4 Homogeneous mixtures | back 4 a. are always liquids. |
front 5 Another name for a homogeneous mixture is | back 5 a. solution. |
front 6 Which of the following statements describes a solid? | back 6 c. Its particles are packed tightly together. |
front 7 Which of the following is a compound? | back 7 d. water. |
front 8 Which of the following is an example of a chemical change? | back 8 a. cooking meat. |
front 9 Which of the following is a heterogeneous mixture? | back 9 d. soil. |
front 10 One difference between a mixture and a compound is that | back 10 b. A compound can be separated into its components by chemical means. |
front 11 All types of matter | back 11 c. have mass and take up space. |
front 12 How many significant figures are in the measurement 2103.2? | back 12 d. 5. |
front 13 Which of these measurements is expressed to three significant figures? | back 13 b. 7.30 x 10^-7 km. |
front 14 The closeness of a measurement to its true value is a measure of its | back 14 b. accuracy. |
front 15 The temperature reading of -14⁰C corresponds to a Kelvin reading of | back 15 a. 259 K. |
front 16 A student measures a volume as 250 mL, whereas the correct volume is 240 mL. What is the percent error? | back 16 b. -4.2%. |
front 17 What is the density of an object having a mass of 8 g and a volume of 25 mL? | back 17 b. 0.32 g/mL. |
front 18 Which of the following has the metric prefixes in order from largest to smallest? | back 18 d. kilo, deca, deci, nano. |
front 19 What is the result of converting 48 m to centimeters? | back 19 c. 4800 cm. |
front 20 A metric unit of volume is the | back 20 a. L. |
front 21 Which of the following conversions is not correct? | back 21 d. 10 kg = 1 g. |
front 22 A conversion factor: | back 22 d. all of the above. |
front 23 Which of the following is the correct scientific notation for 0.000 008 62? | back 23 d. 8.62 x 10^-6. |
front 24 According to the rules of significant figures, the number of digits that are estimates in measurement is | back 24 a. one. |
front 25 How many centimeters are in 25 kilometers? | back 25 b. 2.5 x 10^5 cm. |
front 26 What is the volume of 25.0 g of copper if the density of copper is 8.9 g/cm³? | back 26 a. 2.8 cm³. |
front 27 Express the product of 4.0 x 10^-2 m and 8.1 x 10^2 m using the correct number of significant digits. | back 27 b. 3.0 x 10^2 m². |
front 28 The sum of protons and neutrons in an atom equals the | back 28 d. mass number. |
front 29 Light is emitted by an atom when | back 29 a. an electron drops from a higher to a lower energy level. |
front 30 Dalton theorized that atoms are indivisible and that all atoms of an element are identical. Scientists now know that | back 30 c. atoms are all divisible. |
front 31 Why did JJ Thomson believe that electrons (negatively charged particles) must be a part of the atom? | back 31 c. Cathode rays are attracted to positive magnetic plates. |
front 32 What is the frequency of radiation with a wavelength of 5.00 x 10^-8 m? | back 32 d. 6.00 x 10^15 s^-1. |
front 33 Calculate the wavelength of the yellow light emitted if the frequency of the radiation is 5.09 x 10^14 Hz. | back 33 b. 5.89 x 10^-7 m. |
front 34 What is the energy of a photon of microwave radiation with a frequency of 3.20 x 10^11 s^-1? | back 34 c. 2.12 x 10^-22 J. |
front 35 What is the frequency of a wavelength that has a photon energy of 3.84 x 10^-19 J? | back 35 a. 5.80 x 10^14/s. |
front 36 Which of the following visible light colors has the greatest amount of energy? | back 36 c. violet. |
front 37 Which of the following sublevels has the greatest amount of energy? | back 37 a. sublevel F. |
front 38 The nucleus of an atom is | back 38 a. positively charged and has a high density. |
front 39 What is the atomic number of an element? | back 39 The atomic number of an element is the number of protons in the nucleus of an atom of that element. |
front 40 What is the mass number of an atom? | back 40 The mass number is the total number of protons and neutrons in an atom's nucleus. |
front 41 What is a cation? | back 41 A cation is an atom or group of atoms that has a positive charge due to the loss of one or more electrons. |
front 42 What is an anion? | back 42 An anion is an atom or group of atoms that has a negative charge due to the gain of one or more electrons. |
front 43 What determines the identity of an element? | back 43 The identity of an element is determined by the number of protons in its atoms. |
front 44 What are isotopes? | back 44 Isotopes are atoms of the same element that have the same number of protons but different numbers of neutrons. |
front 45 What is electronegativity? | back 45 Electronegativity is a measure of the tendency of an atom to attract a bonding pair of electrons. |
front 46 What is the maximum number of electrons in the first three energy levels? | back 46 The maximum number of electrons in the first, second, and third energy levels is 2, 8, and 18, respectively. |
front 47 What is the electron configuration for bromine? | back 47 The electron configuration for bromine is 1s2 2s2 2p6 3s2 3p5. |
front 48 What is the significance of the periodic table? | back 48 The periodic table organizes elements based on increasing atomic number and groups elements with similar properties. |
front 49 What are transition metals? | back 49 Transition metals are elements found in the d-block of the periodic table, known for their ability to form variable oxidation states. |
front 50 What is the most electronegative element? | back 50 The most electronegative element is fluorine (F). |
front 51 What is ionization energy? | back 51 Ionization energy is the energy required to remove an electron from an atom in its gaseous state. |
front 52 What is the relationship between atomic size and electron configuration? | back 52 Atomic size generally increases down a group and decreases across a period due to increased nuclear charge and electron shielding. |
front 53 What are diatomic molecules? | back 53 Diatomic molecules are molecules composed of two atoms, which can be of the same or different chemical elements. |
front 54 What is the role of neutrons in an atom? | back 54 Neutrons contribute to the mass of an atom and help stabilize the nucleus by offsetting the repulsive forces between protons. |
front 55 What is the average atomic mass? | back 55 The average atomic mass is the weighted average of the masses of an element's isotopes, based on their natural abundance. |
front 56 What is the difference between a neutral atom and an ion? | back 56 A neutral atom has an equal number of protons and electrons, while an ion has a different number of protons and electrons, resulting in a charge. |
front 57 What is the significance of the outermost energy level? | back 57 The outermost energy level determines an atom's chemical properties and its ability to bond with other atoms. |
front 58 What is a quantum of energy? | back 58 A quantum of energy is the smallest discrete amount of energy that can be absorbed or emitted by an atom. |
front 59 What is the difference between alpha, beta, and gamma radiation? | back 59 Alpha radiation consists of helium nuclei, beta radiation consists of electrons or positrons, and gamma radiation consists of high-energy photons. |
front 60 What is the electron configuration for calcium? | back 60 The electron configuration for calcium is 1s2 2s2 2p6 3s2 3p6 4s2. |
front 61 What is the trend of ionization energy across a period? | back 61 Ionization energy generally increases across a period due to increasing nuclear charge. |
front 62 What is the trend of atomic radius down a group? | back 62 Atomic radius generally increases down a group due to the addition of energy levels. |
front 63 What is a metalloid? | back 63 Metalloids are elements that have properties of both metals and nonmetals and are found along the zig-zag line on the periodic table. |
front 64 What is the significance of the d-block in the periodic table? | back 64 The d-block contains transition metals, which are characterized by their ability to form various oxidation states and complex ions. |
front 65 What is the energy change that accompanies the loss of an electron from an atom? | back 65 It is called ionization energy. |
front 66 How does ionization energy change as you move down a group in the periodic table? | back 66 Ionization energy generally decreases as you move down a group. |
front 67 Which of the following are listed in order of increasing electronegativity? | back 67 The correct order is sulfur, oxygen, fluorine. |
front 68 Which of the following is NOT true about an alpha particle? | back 68 An alpha particle has a +1 charge (this is false; it has a +2 charge). |
front 69 What characterizes an unstable nucleus? | back 69 An unstable nucleus may have too few or too many neutrons and loses energy by emitting radiation. |
front 70 What happens during beta emission of an isotope? | back 70 The atomic number changes, but the mass number remains the same. |
front 71 What are transuranium elements? | back 71 They are elements with atomic numbers above 92 and are sometimes radioactive. |
front 72 What must a transmutation reaction involve? | back 72 A change in the number of protons in the nucleus of the atom. |
front 73 Which of these is NOT a characteristic of most ionic compounds? | back 73 Ionic compounds typically have a low melting point (this is false; they usually have high melting points). |
front 74 Which element would most likely form an ionic compound with chlorine? | back 74 Lithium would most likely form an ionic compound with chlorine. |
front 75 What is the electron configuration of the fluoride ion (F-)? | back 75 The electron configuration is the same as that of the neon atom. |
front 76 What is the charge on an aluminum ion after it loses its valence electrons? | back 76 The charge on the resulting ion is 3+. |
front 77 What is true about cations and anions? | back 77 Cations form when an atom loses electrons, while anions form when an atom gains electrons. |
front 78 What is the lowest whole-number ratio of ions in an ionic compound called? | back 78 It is called a formula unit. |
front 79 What defines an ionic compound? | back 79 An ionic compound is electrically neutral and composed of anions and cations held together by ionic bonds. |
front 80 What is the chemical formula for the ionic compound formed when calcium and nitrogen react? | back 80 The formula is Ca3N2. |
front 81 What is a mixture of two or more elements, at least one of which is a metal? | back 81 It is called an alloy. |
front 82 Which element does NOT exist as a diatomic molecule? | back 82 Helium does not exist as a diatomic molecule. |
front 83 Which compound is NOT covalent? | back 83 KCl is not a covalent compound; it is ionic. |
front 84 How many valence electrons does any halogen have? | back 84 Any halogen has 7 valence electrons. |
front 85 What is a diatomic molecule with a triple covalent bond? | back 85 N2 is a diatomic molecule with a triple covalent bond. |
front 86 What type of bond forms when a bonding pair of electrons is unequally shared? | back 86 The bond is called a polar covalent bond. |
front 87 What are the possible shapes of a three-atom molecule? | back 87 A three-atom molecule can be linear, pyramidal, or tetrahedral. |
front 88 What is the bond angle for any tetrahedral molecule? | back 88 The bond angle is approximately 109.5°. |
front 89 How do the melting and boiling points of most molecular compounds compare to those of ionic compounds? | back 89 They are generally lower than those of most ionic compounds. |
front 90 Which molecule contains the most polar bond? | back 90 HF contains the most polar bond. |
front 91 Which diatomic molecule contains a single covalent bond? | back 91 F2 contains a single covalent bond. |
front 92 What occurs when a covalent bond forms? | back 92 A covalent bond forms when atoms share electrons. |
front 93 What is a coordinate covalent bond? | back 93 It is formed when both bonding electrons come from one atom. |
front 94 What is the molecular shape of carbon tetrachloride (CCl4)? | back 94 The shape is tetrahedral. |
front 95 What is the correct name for the ion Fe2+? | back 95 The correct name is iron (II) ion. |