1. Which of the following elements is NOT one of the six that make up 98% of most organisms' body...
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Transcript of 1. Which of the following elements is NOT one of the six that make up 98% of most organisms' body...
• 1. Which of the following elements is NOT one of the six that make up 98% of most organisms' body weight?
• A. hydrogen B. nitrogen C. carbon D. iron___
•2. All atoms of a certain element have the same number of protons.
• True False___
•3. All matter is composed of certain basic substances called elements.
• True False___
•4. The three isotopes of carbon 12C, 13C and 14C have different numbers of _______?
• A. electrons B. protons C. neutrons___
•5. Protons have a __________ electrical charge.
• A. positive B. negative C. neutral
___
•6. Electrons always have the same amount of potential energy.
• True False___
•7. The atomic number of an atom is the same as __________.
• A. the atom's mass B. the number of protons the atom has C. the number of neutrons the atom has___
•8. If an atom has an atomic number of 17 and an atomic mass of 35, the number of neutrons in its nucleus equals _____.
• A. 17 B. 18 C. 35 D. 52
___
•9. Electrons with the least amount of potential energy are located in the __________ shell.
• A. L B. K C. M___
•10. If an atom with an atomic number of 9 and an atomic mass of 19 is electrically neutral, it has __________ electrons.
• A. 9 B. 10 C. 19 D. 28
___
•11. Radioactive isotopes are used to __________.
• A. determine the age of fossils B. trace chemicals during biochemical reactions C. detect thyroid abnormalities D. all of the above___
•12. Electrons that are farther from the nucleus have more potential energy than electrons closer to the nucleus.
• True False___
•13. The subatomic particle with an atomic mass of one and a neutral charge is a(n) __________.
• A. proton B. electron C. neutron___
•14. The nucleus contains ________.
• A. protons B. electrons C. neutrons D. A and C___
•15. Electron shells, other than the first one, can contain up to eight electrons.
• True False___
•16. An electrically neutral atom with an atomic number of 7 will have _____ electron shell(s).
• A. one B. two C. three D. four
___
•17. Electrically neutral magnesium (atomic number 12) is an example of an inert (non reactive) atom.
• True False___
•18. How many carbon atoms are there in a molecule of glucose, C6H12O6?
• A. 1 B. 6 C. 12 D. 24
___
•19. If a chemical equation is balanced, there are equal numbers of each specific atom on both sides of the arrow.
• True False___
•20. An atom of hydrogen (atomic number = 1; atomic mass = 1) has one proton and no neutrons.
• True False___
•21. Which of the following is an inert (non-reactive) atom?
• A. hydrogen; atomic number = 1 B. oxygen; atomic number = 8 C. neon; atomic number = 10 D. chlorine; atomic number = 17___
•22. The sodium ion (Na+) has 12 protons (atomic number of Na = 11).
• True False___
•23. Which bond is most easily broken?
• A. a hydrogen bond B. a triple covalent bond C. a single covalent bond
___
•24. What type of bond is formed when atoms share electrons?
• A. ionic B. covalent C. hydrogen___
•25. Chlorine (atomic number = 17) needs _____ electron(s) to fill its outermost electron shell.
• A. no B. one C. seven D. eight
___
•26. Electrically neutral atoms are called ions.
• True False___
•27. In a __________ covalent bond, two atoms share two pairs of electrons.
• A. single B. double C. triple___
•28. An equal sharing of electrons creates a __________ bond.
• A. polar covalent B. ionic C. hydrogen D. non-polar covalent___
•29. Which of the following is most likely to form an ionic bond with Cl-?
• A. F- B. Na+ C. He D. O2
___
•30. Which of the following is an example of a compound?
• A. O2 B. Na+ C. CO2 D. Ne
___
•31. What type of bond will form between 2 atoms of nitrogen (atomic number = 7) to form the gas N2?
• A. ionic B. triple covalent C. single covalent D. none
___
•32. An atom with one electron in its outermost shell tends to be an electron donor.
• True False___
•33. A dashed line between atoms represents a(n) _____ bond.
• A. hydrogen B. single covalent bond C. ionic D. polar covalent bond
___
•34. The chlorine ion (Cl-) has 17 protons and 18 electrons.
• True False___
•35. The three dimensional shape of a molecule affects its ability to function.
• True False___
•36. Hydrogen bonds form when ___________.
• A. atoms share electrons B. a slightly negative atom is attracted to a slightly positive atom C. atoms gain electrons D. atoms lose protons
___
•37. Energy is __________.
• A. required for a bond to form B. released when a bond is broken C. A and B___
•38. An attraction between oppositely charged atoms forms a _____ bond.
• A. polar covalent B. triple covalent C. hydrogen D. ionic___
•39. The atom with greater electronegativity will have a slight positive charge in a polar covalent bond.
• True False___
•40. Water is a polar molecule.
• True False___
•41. A negative ion _____.
• A. has accepted an electron from another atom B. is radioactive and can be used to determine the age of fossils C. will form a polar covalent bond with another atom D. all of the above
___
•42. The calcium ion (Ca2+) _____.
• A. has accepted two protons B. has given away two electrons C. will form a covalent bond with the chlorine ion (Cl-) D. all of the above
___
•43. Water molecules are _____.
• A. polar B. hydrogen bonded to one another C. cohesive D. all of the above___
•44. Internal body fluids are kept at a near neutral pH by buffers.
• True False___
•45. A pH of 7 is _____.
• A. acidic B. basic C. neutral___
•46. Which of the following has a basic pH?
• A. lemon juice B. milk of magnesia C. tomatoes D. hydrochloric acid
___
•47. Hydrogen bonding ___________.
• A. causes water molecules to cling to each other B. allows water to absorb a lot of heat without a huge change in temperature C. must be broken to convert water to steam
D. all of the above___
•48. All living things are _____ water.
• A. less than 10% B. 10-30% C. 40-60% D. 70-90%___
•49. Which property of water is attributed to its polarity?
• A. It resists changes in temperature. B. It has a high surface tension. C. It is the universal solvent. D. It is less dense as a solid than as a liquid.___
•50. Which property of water is responsible for facilitating the flow of water upwards in a tree?
• A. It resists changes of state (from liquid to ice or liquid to steam). B. It is cohesive and adhesive. C. It is the universal solvent. D. It is less dense as a solid than as a liquid.
___
•51. Molecules that attract water are described as hydrophilic.
• True False___
•52. Aquatic living things are able to survive the winter thanks to which property of water?
• A. It is less dense as a solid than as a liquid.
B. It is cohesive and adhesive. C. It is the universal solvent D. It resists changes of state (from liquid to ice or liquid to steam).
___
•53. Which of the following is best described as hydrophobic?
• A. water B. oil C. sugar D. salt
___
•54. Water would still freeze at 0°C and boil at 100°C without hydrogen bonding.
• True False___
•55. A solution with a pH of 5 has 10 times more hydrogen ions (H+) than a solution with a pH of 6.
• True False___
•56. Any pH below _____ is acidic.
• A. one B. five C. seven D. twelve___
•57. Acid rain is a problem because ___________.
• A. it adversely affects fish living in lakes B. it weakens trees by leaching away nutrients C. it damages marble and limestone buildings and monuments D. all of the above___
•58. Sulfur dioxide and nitrogen oxides combine with atmospheric water to produce sulfuric acid and nitric acid which falls to earth as acid rain.
• True False___
•59. Which of the following is an example of an acid?
• A. HCl B. NaCl C. NaOH D. CO2
___
•60. Water is less dense at 4°C than at 0°C which is why water freezes from the bottom upwards.
• True False___