Q&A Hero

Q: Fullerenes are molecules composed of only carbon atoms. A molecule of one fullerene has a mass of 1.675 g. How many carbon atoms are in a single molecule of this fullerene molecule? A) 76 B) 70 C) 60 D) 84

Q: Fullerenes are molecules composed of only carbon atoms. A molecule of one fullerene has a mass of 1.516 g. How many carbon atoms are in a single molecule of this fullerene molecule? A) 76 B) 70 C) 60 D) 84

Q: Fullerenes are molecules composed of only carbon atoms. One fullerene is , a carbon molecule containing 70 carbon atoms. What is the mass of one molecule? A) 1.40 1 g B) 9.68 g C) 2.85 g D) 3.28 g

Q: Fullerenes are molecules composed of only carbon atoms. One fullerene is , a carbon molecule containing 60 carbon atoms. What is the mass of one molecule? A) 1.20 g B) 8.29 g C) 3.32 g D) 4.41 g

Q: The atoms of a particular element all have the same number of protons as neutrons. Which of the following must be true? A) The atomic weight must be a whole number. B) The mass number for each atom must equal the atomic weight of the element. C) The mass number must be exactly twice the atomic number for each atom. D) All of the above are true.

Q: Identify the chemical symbol of element Q in Q. A) Br B) Hg C) Pd D) Se

Q: How many protons (p), neutrons (n), and electrons (e) are in one atom of Mg? A) 12 p, 12 n, 12 e B) 12 p, 11 n, 12 e C) 12 p, 11 n, 10 e D) 12 p, 11 n, 14 e

Q: What is the chemical symbol for an atom that has 29 protons and 36 neutrons? A) Cu B) Kr C) N D) Tb

Q: How many protons (p) and neutrons (n) are in an atom of calcium-46? A) 20 p, 26 n B) 20 p, 46 n C) 26 p, 20 n D) 46 p, 60 n

Q: How many protons (p) and neutrons (n) are in an atom of Sr? A) 38 p, 52 n B) 38 p, 90 n C) 52 p, 38 n D) 90 p, 38 n

Q: Boron-9 can be represented as A) Be. B) B. C) B. D) B.

Q: The isotope represented by C is named A) carbon-6. B) carbon-7. C) carbon-13. D) carbon-19.

Q: Which of the following represent isotopes? A: [ ] B: [ ] C: [ ] D: [ ] A) A and B B) A and C C) A and D D) C and D

Q: Which of the following two atoms are isotopes? A) Ar and Ca B) C and C C) Cl and Br D) Mg and C

Q: Which subatomic particle has the smallest mass? A) a proton B) a neutron C) an electron D) an alpha particle

Q: Most of the alpha particles directed at a thin gold foil in Rutherford's experiment A) bounced directly back from the foil. B) passed directly through the foil undeflected. C) passed through the foil but were deflected at an angle. D) were absorbed by the foil.

Q: The existence of neutrons in the nucleus of an atom was demonstrated by A) Millikan's oil drop experiment. B) Rutherford's gold foil experiment. C) Thomson's cathode ray tube experiment. D) None of the above.

Q: The current model of the atom in which essentially all of an atom's mass is contained in a very small nucleus, whereas most of an atom's volume is due to the space in which the atom's electrons move was established by A) Millikan's oil drop experiment. B) Rutherford's gold foil experiment. C) Thomson's cathode ray tube experiment. D) None of the above.

Q: The charge-to-mass ratio of an electron was established by A) Millikan's oil drop experiment. B) Rutherford's gold foil experiment. C) Thomson's cathode ray tube experiment. D) None of the above.

Q: The existence of electrons in atoms of all elements was demonstrated by A) Millikan's oil drop experiment. B) Rutherford's gold foil experiment. C) Thomson's cathode ray tube experiment. D) None of the above.

Q: Elements A and Q form two compounds. The ratio (mass Q)/(mass A) for compound one is 0.271 and ratio (mass Q)/(mass A) for compound two is 0.362. If compound one has the chemical formula AQ, what is the chemical formula for compound two? A) A3Q4 B) A2Q3 C) AQ2 D) AQ3

Q: Elements A and Q form two compounds, AQ and A2Q. Which of the following must be true? A) (mass Q)/(mass A) is one for AQ, and 1/2 for A2Q. B) (mass Q)/(mass A) for AQ must equal (mass Q)/(mass A) for A2Q. C) (mass Q)/(mass A) for AQ must be 2 times (mass Q)/(mass A) for A2Q. D) (mass Q)/(mass A) for AQ must be 1/2 (mass Q)/(mass A) for A2Q.

Q: Elements A and Q form two compounds, AQ and A2Q3. The mass ratio (mass Q)/(mass A) for AQ is 0.574. What is the mass ratio (mass Q)/(mass A) for A2Q3? A) 0.383 B) 0.861 C) 1.16 D) 2.61

Q: Which of the following is not explained by Dalton's atomic theory? A) conservation of mass during a chemical reaction B) the existence of more than one isotope of an element C) the law of definite proportions D) the law of multiple proportions

Q: Which of the following is a part of Dalton's atomic theory? A) Atoms are rearranged but not changed during a chemical reaction. B) Atoms break down during radioactive decay. C) Atoms contain protons, neutrons, and electrons. D) Isotopes of the same element have different masses.

Q: Which of the following statements is not a postulate of Dalton's atomic theory? A) Each element is characterized by the mass of its atoms. B) Atoms are composed of protons, neutrons, and electrons. C) Chemical reactions only rearrange atomic combinations. D) Elements are composed of atoms.

Q: The observation that hydrogen and oxygen can react to form two compounds with different chemical and physical properties, one having an O:H mass ratio = 8:1 and the other having an O:H mass ratio = 16:1 is consistent with the law of A) definite proportions. B) energy conservation. C) mass conservation. D) multiple proportions.

Q: A sample of pure calcium fluoride with a mass of 15.0 g contains 7.70 g of calcium. How much calcium is contained in 45.0 g of calcium fluoride? A) 2.56 g B) 7.70 g C) 15.0 g D) 23.1 g

Q: A sample of pure lithium carbonate contains 18.8% lithium by mass. What is the % lithium by mass in a sample of pure lithium carbonate that has twice the mass of the first sample? A) 9.40% B) 18.8% C) 37.6% D) 75.2%

Q: The observation that 4.0 g of hydrogen reacts with 32.0 g of oxygen to form a product with O:H mass ratio = 8:1, and 6.0 g of hydrogen reacts with 48.0 g of oxygen to form the same product with O/H mass ratio = 8:1 is evidence for the law of A) definite proportions. B) energy conservation. C) mass conservation. D) multiple proportions.

Q: The observation that 15.0 g of hydrogen reacts with 120.0 g of oxygen to form 135.0 g of water is evidence for the law of A) definite proportions. B) energy conservation. C) mass conservation. D) multiple proportions.

Q: Which element indicated by letter in the following periodic table is the best conductor of electricity and heat? A) A B) B C) C D) D

Q: Which element indicated by letter in the following periodic table is the poorest conductor of electricity and heat? A) A B) B C) C D) D

Q: Which element indicated by letter in the following periodic table is a gas at room temperature? A) A B) B C) C D) D

Q: Which element indicated by letter in the following periodic table is a gas at room temperature? A) A B) B C) C D) D

Q: Which element indicated by letter in the following periodic table is a gas at room temperature? A) A B) B C) C D) D

Q: Which element indicated by letter in the following periodic table reacts rapidly with water to form an alkaline solution? A) A B) B C) C D) D

Q: Which element indicated by letter in the following periodic table reacts rapidly with water to form an alkaline solution? A) A B) B C) C D) D

Q: Which element indicated by letter in the following periodic table reacts rapidly with water to form an alkaline solution? A) A B) B C) C D) D

Q: Which element is most chemically similar to the element indicated by the letter E in the following periodic table? A) A B) B C) C D) D

Q: Which element is most chemically similar to the element indicated by the letter E in the following periodic table? A) A B) B C) C D) D

Q: Which element is most chemically similar to the element indicated by the letter E in the following periodic table? A) A B) B C) C D) D

Q: What group of elements does the shaded area in the following periodic table indicate? A) gases B) metals C) nonmetals D) semimetals

Q: What group of elements does the shaded area in the following periodic table indicate? A) gases B) metals C) nonmetals D) semimetals

Q: What group of elements does the shaded area in the following periodic table indicate? A) gases B) metals C) nonmetals D) semimetals

Q: What group of elements does the shaded area in the following periodic table indicate? A) alkali metals B) alkaline earth metals C) halogens D) noble gases

Q: What group of elements does the shaded area in the following periodic table indicate? A) alkali metals B) alkaline earth metals C) halogens D) noble gases

Q: What group of elements does the shaded area in the following periodic table indicate? A) alkali metals B) alkaline earth metals C) halogens D) noble gases

Q: What group of elements does the shaded area in the following periodic table indicate? A) alkali metals B) alkaline earth metals C) halogens D) noble gases

Q: 1What group of elements does the shaded area in the following periodic table indicate? A) alkali metals B) alkaline earth metals C) inner transition metals D) transition metals

Q: What group of elements does the shaded area in the following periodic table indicate? A) alkali metals B) alkaline earth metals C) inner transition metals D) transition metals

Q: All of the following elements are nonmetals except A) antimony. B) carbon. C) hydrogen. D) oxygen.

Q: Gaseous elements characterized by low reactivity are found in group ________ of the periodic table. A) 5A B) 6A C) 7A D) 8A

Q: Which one of the following elements is a poor conductor of heat and electricity? A) copper B) fluorine C) iron D) lead

Q: Which of the following elements is a good conductor of heat and electricity? A) carbon B) chlorine C) neon D) zinc

Q: Which of the following elements is classified as a semimetal? A) calcium B) germanium C) fluorine D) uranium

Q: Which of the following elements is not a solid at room temperature? A) Ag B) Al C) Br D) Fe

Q: Which group of elements reacts violently with water? A) halogens B) noble gases C) alkali metals D) alkaline earth metals

Q: Which of the following elements is a liquid at room temperature? A) chlorine B) helium C) mercury D) sodium

Q: Which group 5A element is most metallic? A) N B) P C) Sb D) Bi

Q: Which group 1A element is not a metal? A) H B) Li C) Fr D) none of these

Q: Which of the following underlined items is not an extensive property? A) the color of a cobalt compound B) the diameter of a soap bubble C) the mass of a diamond D) the volume of a glucose solution

Q: Which of the following underlined items is not an intensive property? A) A chemical reaction requires 3.00 g of oxygen. B) Solid copper hydroxide is blue colored. C) The density of helium at 25C is 1.64 10-4 g/cm3. D) The melting point of aluminum metal is 933 K.

Q: Which of the following statements does not describe a chemical property of oxygen? A) Iron will rust in the presence of oxygen. B) Oxygen combines with carbon to form carbon dioxide gas. C) The pressure is caused by collision of oxygen molecules with the sides of a container. D) When coal is burned in oxygen, the process is called combustion.

Q: Which of the following statements does not describe a physical property of chlorine? A) Chlorine combines with sodium to form table salt. B) The color of chlorine gas is green. C) The density of chlorine gas at standard temperature and pressure is 3.17 g/L. D) The freezing point of chlorine is -101C.

Q: Which horizontal row of the periodic table contains the most elements? A) row 4 B) row 5 C) row 6 D) They all contain the same number of elements.

Q: Elements in a periodic group have similar A) chemical properties. B) densities. C) masses. D) physical properties.

Q: Most elements in the periodic table are A) metals. B) non-metals. C) noble gases. D) semi-metals.

Q: Calcium belongs to the ________ group of the periodic table. A) alkali metal B) alkaline earth C) halogen D) noble gas

Q: Argon belongs to the ________ group of the periodic table. A) alkali metal B) alkaline earth C) halogen D) noble gas

Q: Bromine belongs to the ________ group of the periodic table. A) alkali metal B) alkaline earth metal C) halogen D) noble gas

Q: Lithium belongs to the ________ group of the periodic table. A) alkali metal B) alkaline earth metal C) halogen D) noble gas

Q: The vertical columns of the periodic table are called A) groups. B) periods. C) triads. D) elements.

Q: The horizontal rows of the periodic table are called A) groups. B) periods. C) triads. D) elements.

Q: Which is not true? A) Mendeleev ended each row in his periodic table with an inert gas. B) Mendeleev left gaps in his periodic table for undiscovered elements. C) Mendeleev ordered the elements in his periodic table by atomic weight. D) Mendeleev's periodic table predated the concept of electron configuration.

Q: Mendeleev arranged the elements according to A) atomic number and atomic weight. B) atomic weight and chemical reactivity. C) electron configuration and atomic weight. D) physical state and relative abundance.

Q: What is the chemical symbol for tin? A) Sb B) Sn C) Ta D) Ti

Q: U undergoes alpha decay producing one alpha particle and a single nuclide. To balance the equation ________ and ________ must be added to the right side of the equation below.U -> ? + ?

Q: The number of protons, neutrons, and total nucleons in Ru are ________, ________, and ________, respectively.

Q: The number of neutrons in a neutral atom of uranium-238 is ________.